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synced 2024-08-25 10:45:59 +00:00
![Junio C Hamano](/assets/img/avatar_default.png)
When fsck validates a commit or a tag, it scans each line in the header of the object using helper functions such as "start_with()", etc. that work on a NUL terminated buffer, but beforea1e920a0
(index-pack: terminate object buffers with NUL, 2014-12-08), the validation functions were fed the object data in a piece of memory that is not necessarily terminated with a NUL. We added a helper function require_end_of_header() to be called at the beginning of these validation functions to insist that the object data contains an empty line before its end. The theory is that the validating functions will notice and stop when it hits an empty line as a normal end of header (or a required header line that is missing) without scanning past the end of potentially not NUL-terminated buffer. But the theory forgot that in the older days, Git itself happily created objects with only the header lines without a body. This caused Git 2.2 and later to issue an unnecessary warning in some existing repositories. Witha1e920a0
, we do not need to require an empty line (or the body) in these objects to safely parse and validate them. Drop the offending "must have an empty line" check from this helper function, while keeping the other check to make sure that there is no NUL in the header part of the object, and adjust the name of the helper to what it does accordingly. Noticed-by: Wolfgang Denk <wd@denx.de> Helped-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
498 lines
14 KiB
C
498 lines
14 KiB
C
#include "cache.h"
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#include "object.h"
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#include "blob.h"
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#include "tree.h"
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#include "tree-walk.h"
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#include "commit.h"
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#include "tag.h"
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#include "fsck.h"
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#include "refs.h"
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static int fsck_walk_tree(struct tree *tree, fsck_walk_func walk, void *data)
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{
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struct tree_desc desc;
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struct name_entry entry;
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int res = 0;
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if (parse_tree(tree))
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return -1;
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init_tree_desc(&desc, tree->buffer, tree->size);
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while (tree_entry(&desc, &entry)) {
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int result;
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if (S_ISGITLINK(entry.mode))
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continue;
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if (S_ISDIR(entry.mode))
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result = walk(&lookup_tree(entry.sha1)->object, OBJ_TREE, data);
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else if (S_ISREG(entry.mode) || S_ISLNK(entry.mode))
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result = walk(&lookup_blob(entry.sha1)->object, OBJ_BLOB, data);
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else {
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result = error("in tree %s: entry %s has bad mode %.6o",
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sha1_to_hex(tree->object.sha1), entry.path, entry.mode);
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}
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if (result < 0)
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return result;
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if (!res)
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res = result;
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}
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return res;
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}
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static int fsck_walk_commit(struct commit *commit, fsck_walk_func walk, void *data)
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{
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struct commit_list *parents;
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int res;
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int result;
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if (parse_commit(commit))
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return -1;
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result = walk((struct object *)commit->tree, OBJ_TREE, data);
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if (result < 0)
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return result;
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res = result;
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parents = commit->parents;
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while (parents) {
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result = walk((struct object *)parents->item, OBJ_COMMIT, data);
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if (result < 0)
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return result;
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if (!res)
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res = result;
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parents = parents->next;
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}
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return res;
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}
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static int fsck_walk_tag(struct tag *tag, fsck_walk_func walk, void *data)
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{
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if (parse_tag(tag))
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return -1;
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return walk(tag->tagged, OBJ_ANY, data);
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}
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int fsck_walk(struct object *obj, fsck_walk_func walk, void *data)
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{
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if (!obj)
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return -1;
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switch (obj->type) {
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case OBJ_BLOB:
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return 0;
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case OBJ_TREE:
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return fsck_walk_tree((struct tree *)obj, walk, data);
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case OBJ_COMMIT:
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return fsck_walk_commit((struct commit *)obj, walk, data);
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case OBJ_TAG:
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return fsck_walk_tag((struct tag *)obj, walk, data);
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default:
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error("Unknown object type for %s", sha1_to_hex(obj->sha1));
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return -1;
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}
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}
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/*
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* The entries in a tree are ordered in the _path_ order,
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* which means that a directory entry is ordered by adding
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* a slash to the end of it.
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*
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* So a directory called "a" is ordered _after_ a file
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* called "a.c", because "a/" sorts after "a.c".
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*/
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#define TREE_UNORDERED (-1)
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#define TREE_HAS_DUPS (-2)
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static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, const char *name2)
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{
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int len1 = strlen(name1);
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int len2 = strlen(name2);
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int len = len1 < len2 ? len1 : len2;
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unsigned char c1, c2;
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int cmp;
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cmp = memcmp(name1, name2, len);
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if (cmp < 0)
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return 0;
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if (cmp > 0)
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return TREE_UNORDERED;
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/*
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* Ok, the first <len> characters are the same.
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* Now we need to order the next one, but turn
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* a '\0' into a '/' for a directory entry.
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*/
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c1 = name1[len];
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c2 = name2[len];
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if (!c1 && !c2)
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/*
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* git-write-tree used to write out a nonsense tree that has
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* entries with the same name, one blob and one tree. Make
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* sure we do not have duplicate entries.
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*/
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return TREE_HAS_DUPS;
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if (!c1 && S_ISDIR(mode1))
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c1 = '/';
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if (!c2 && S_ISDIR(mode2))
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c2 = '/';
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return c1 < c2 ? 0 : TREE_UNORDERED;
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}
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static int fsck_tree(struct tree *item, int strict, fsck_error error_func)
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{
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int retval;
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int has_null_sha1 = 0;
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int has_full_path = 0;
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int has_empty_name = 0;
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int has_dot = 0;
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int has_dotdot = 0;
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int has_dotgit = 0;
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int has_zero_pad = 0;
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int has_bad_modes = 0;
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int has_dup_entries = 0;
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int not_properly_sorted = 0;
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struct tree_desc desc;
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unsigned o_mode;
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const char *o_name;
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init_tree_desc(&desc, item->buffer, item->size);
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o_mode = 0;
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o_name = NULL;
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while (desc.size) {
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unsigned mode;
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const char *name;
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const unsigned char *sha1;
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sha1 = tree_entry_extract(&desc, &name, &mode);
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has_null_sha1 |= is_null_sha1(sha1);
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has_full_path |= !!strchr(name, '/');
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has_empty_name |= !*name;
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has_dot |= !strcmp(name, ".");
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has_dotdot |= !strcmp(name, "..");
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has_dotgit |= !strcmp(name, ".git");
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has_zero_pad |= *(char *)desc.buffer == '0';
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update_tree_entry(&desc);
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switch (mode) {
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/*
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* Standard modes..
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*/
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case S_IFREG | 0755:
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case S_IFREG | 0644:
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case S_IFLNK:
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case S_IFDIR:
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case S_IFGITLINK:
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break;
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/*
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* This is nonstandard, but we had a few of these
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* early on when we honored the full set of mode
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* bits..
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*/
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case S_IFREG | 0664:
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if (!strict)
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break;
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default:
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has_bad_modes = 1;
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}
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if (o_name) {
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switch (verify_ordered(o_mode, o_name, mode, name)) {
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case TREE_UNORDERED:
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not_properly_sorted = 1;
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break;
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case TREE_HAS_DUPS:
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has_dup_entries = 1;
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break;
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default:
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break;
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}
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}
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o_mode = mode;
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o_name = name;
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}
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retval = 0;
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if (has_null_sha1)
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retval += error_func(&item->object, FSCK_WARN, "contains entries pointing to null sha1");
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if (has_full_path)
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retval += error_func(&item->object, FSCK_WARN, "contains full pathnames");
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if (has_empty_name)
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retval += error_func(&item->object, FSCK_WARN, "contains empty pathname");
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if (has_dot)
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retval += error_func(&item->object, FSCK_WARN, "contains '.'");
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if (has_dotdot)
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retval += error_func(&item->object, FSCK_WARN, "contains '..'");
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if (has_dotgit)
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retval += error_func(&item->object, FSCK_WARN, "contains '.git'");
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if (has_zero_pad)
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retval += error_func(&item->object, FSCK_WARN, "contains zero-padded file modes");
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if (has_bad_modes)
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retval += error_func(&item->object, FSCK_WARN, "contains bad file modes");
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if (has_dup_entries)
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retval += error_func(&item->object, FSCK_ERROR, "contains duplicate file entries");
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if (not_properly_sorted)
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retval += error_func(&item->object, FSCK_ERROR, "not properly sorted");
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return retval;
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}
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static int verify_headers(const void *data, unsigned long size,
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struct object *obj, fsck_error error_func)
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{
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const char *buffer = (const char *)data;
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unsigned long i;
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for (i = 0; i < size; i++) {
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switch (buffer[i]) {
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case '\0':
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return error_func(obj, FSCK_ERROR,
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"unterminated header: NUL at offset %d", i);
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case '\n':
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if (i + 1 < size && buffer[i + 1] == '\n')
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return 0;
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}
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}
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/*
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* We did not find double-LF that separates the header
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* and the body. Not having a body is not a crime but
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* we do want to see the terminating LF for the last header
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* line.
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*/
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if (size && buffer[size - 1] == '\n')
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return 0;
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return error_func(obj, FSCK_ERROR, "unterminated header");
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}
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static int fsck_ident(const char **ident, struct object *obj, fsck_error error_func)
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{
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char *end;
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if (**ident == '<')
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return error_func(obj, FSCK_ERROR, "invalid author/committer line - missing space before email");
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*ident += strcspn(*ident, "<>\n");
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if (**ident == '>')
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return error_func(obj, FSCK_ERROR, "invalid author/committer line - bad name");
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if (**ident != '<')
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return error_func(obj, FSCK_ERROR, "invalid author/committer line - missing email");
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if ((*ident)[-1] != ' ')
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return error_func(obj, FSCK_ERROR, "invalid author/committer line - missing space before email");
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(*ident)++;
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*ident += strcspn(*ident, "<>\n");
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if (**ident != '>')
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return error_func(obj, FSCK_ERROR, "invalid author/committer line - bad email");
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(*ident)++;
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if (**ident != ' ')
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return error_func(obj, FSCK_ERROR, "invalid author/committer line - missing space before date");
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(*ident)++;
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if (**ident == '0' && (*ident)[1] != ' ')
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return error_func(obj, FSCK_ERROR, "invalid author/committer line - zero-padded date");
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if (date_overflows(strtoul(*ident, &end, 10)))
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return error_func(obj, FSCK_ERROR, "invalid author/committer line - date causes integer overflow");
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if (end == *ident || *end != ' ')
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return error_func(obj, FSCK_ERROR, "invalid author/committer line - bad date");
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*ident = end + 1;
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if ((**ident != '+' && **ident != '-') ||
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!isdigit((*ident)[1]) ||
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!isdigit((*ident)[2]) ||
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!isdigit((*ident)[3]) ||
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!isdigit((*ident)[4]) ||
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((*ident)[5] != '\n'))
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return error_func(obj, FSCK_ERROR, "invalid author/committer line - bad time zone");
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(*ident) += 6;
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return 0;
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}
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static int fsck_commit_buffer(struct commit *commit, const char *buffer,
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unsigned long size, fsck_error error_func)
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{
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unsigned char tree_sha1[20], sha1[20];
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struct commit_graft *graft;
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unsigned parent_count, parent_line_count = 0;
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int err;
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if (verify_headers(buffer, size, &commit->object, error_func))
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return -1;
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if (!skip_prefix(buffer, "tree ", &buffer))
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return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'tree' line");
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if (get_sha1_hex(buffer, tree_sha1) || buffer[40] != '\n')
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return error_func(&commit->object, FSCK_ERROR, "invalid 'tree' line format - bad sha1");
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buffer += 41;
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while (skip_prefix(buffer, "parent ", &buffer)) {
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if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n')
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return error_func(&commit->object, FSCK_ERROR, "invalid 'parent' line format - bad sha1");
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buffer += 41;
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parent_line_count++;
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}
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graft = lookup_commit_graft(commit->object.sha1);
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parent_count = commit_list_count(commit->parents);
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if (graft) {
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if (graft->nr_parent == -1 && !parent_count)
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; /* shallow commit */
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else if (graft->nr_parent != parent_count)
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return error_func(&commit->object, FSCK_ERROR, "graft objects missing");
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} else {
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if (parent_count != parent_line_count)
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return error_func(&commit->object, FSCK_ERROR, "parent objects missing");
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}
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if (!skip_prefix(buffer, "author ", &buffer))
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return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'author' line");
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err = fsck_ident(&buffer, &commit->object, error_func);
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if (err)
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return err;
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if (!skip_prefix(buffer, "committer ", &buffer))
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return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'committer' line");
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err = fsck_ident(&buffer, &commit->object, error_func);
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if (err)
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return err;
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if (!commit->tree)
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return error_func(&commit->object, FSCK_ERROR, "could not load commit's tree %s", sha1_to_hex(tree_sha1));
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return 0;
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}
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static int fsck_commit(struct commit *commit, const char *data,
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unsigned long size, fsck_error error_func)
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{
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const char *buffer = data ? data : get_commit_buffer(commit, &size);
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int ret = fsck_commit_buffer(commit, buffer, size, error_func);
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if (!data)
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unuse_commit_buffer(commit, buffer);
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return ret;
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}
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static int fsck_tag_buffer(struct tag *tag, const char *data,
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unsigned long size, fsck_error error_func)
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{
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unsigned char sha1[20];
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int ret = 0;
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const char *buffer;
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char *to_free = NULL, *eol;
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struct strbuf sb = STRBUF_INIT;
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if (data)
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buffer = data;
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else {
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enum object_type type;
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buffer = to_free =
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read_sha1_file(tag->object.sha1, &type, &size);
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if (!buffer)
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return error_func(&tag->object, FSCK_ERROR,
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"cannot read tag object");
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if (type != OBJ_TAG) {
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ret = error_func(&tag->object, FSCK_ERROR,
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"expected tag got %s",
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typename(type));
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goto done;
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}
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}
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if (verify_headers(buffer, size, &tag->object, error_func))
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goto done;
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if (!skip_prefix(buffer, "object ", &buffer)) {
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ret = error_func(&tag->object, FSCK_ERROR, "invalid format - expected 'object' line");
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goto done;
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}
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if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n') {
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ret = error_func(&tag->object, FSCK_ERROR, "invalid 'object' line format - bad sha1");
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goto done;
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}
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buffer += 41;
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if (!skip_prefix(buffer, "type ", &buffer)) {
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ret = error_func(&tag->object, FSCK_ERROR, "invalid format - expected 'type' line");
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goto done;
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}
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eol = strchr(buffer, '\n');
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if (!eol) {
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ret = error_func(&tag->object, FSCK_ERROR, "invalid format - unexpected end after 'type' line");
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goto done;
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}
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if (type_from_string_gently(buffer, eol - buffer, 1) < 0)
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ret = error_func(&tag->object, FSCK_ERROR, "invalid 'type' value");
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if (ret)
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goto done;
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buffer = eol + 1;
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if (!skip_prefix(buffer, "tag ", &buffer)) {
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ret = error_func(&tag->object, FSCK_ERROR, "invalid format - expected 'tag' line");
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goto done;
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}
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eol = strchr(buffer, '\n');
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if (!eol) {
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ret = error_func(&tag->object, FSCK_ERROR, "invalid format - unexpected end after 'type' line");
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goto done;
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}
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strbuf_addf(&sb, "refs/tags/%.*s", (int)(eol - buffer), buffer);
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if (check_refname_format(sb.buf, 0))
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error_func(&tag->object, FSCK_WARN, "invalid 'tag' name: %.*s",
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(int)(eol - buffer), buffer);
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buffer = eol + 1;
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if (!skip_prefix(buffer, "tagger ", &buffer))
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/* early tags do not contain 'tagger' lines; warn only */
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error_func(&tag->object, FSCK_WARN, "invalid format - expected 'tagger' line");
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else
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ret = fsck_ident(&buffer, &tag->object, error_func);
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done:
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strbuf_release(&sb);
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free(to_free);
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return ret;
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}
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static int fsck_tag(struct tag *tag, const char *data,
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unsigned long size, fsck_error error_func)
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{
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struct object *tagged = tag->tagged;
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if (!tagged)
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return error_func(&tag->object, FSCK_ERROR, "could not load tagged object");
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return fsck_tag_buffer(tag, data, size, error_func);
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}
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int fsck_object(struct object *obj, void *data, unsigned long size,
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int strict, fsck_error error_func)
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{
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if (!obj)
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return error_func(obj, FSCK_ERROR, "no valid object to fsck");
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if (obj->type == OBJ_BLOB)
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return 0;
|
|
if (obj->type == OBJ_TREE)
|
|
return fsck_tree((struct tree *) obj, strict, error_func);
|
|
if (obj->type == OBJ_COMMIT)
|
|
return fsck_commit((struct commit *) obj, (const char *) data,
|
|
size, error_func);
|
|
if (obj->type == OBJ_TAG)
|
|
return fsck_tag((struct tag *) obj, (const char *) data,
|
|
size, error_func);
|
|
|
|
return error_func(obj, FSCK_ERROR, "unknown type '%d' (internal fsck error)",
|
|
obj->type);
|
|
}
|
|
|
|
int fsck_error_function(struct object *obj, int type, const char *fmt, ...)
|
|
{
|
|
va_list ap;
|
|
struct strbuf sb = STRBUF_INIT;
|
|
|
|
strbuf_addf(&sb, "object %s:", sha1_to_hex(obj->sha1));
|
|
|
|
va_start(ap, fmt);
|
|
strbuf_vaddf(&sb, fmt, ap);
|
|
va_end(ap);
|
|
|
|
error("%s", sb.buf);
|
|
strbuf_release(&sb);
|
|
return 1;
|
|
}
|