When a caller of sha1_object_info_extended() sets the
"contentp" field in object_info, we call unpack_sha1_rest()
but do not check whether it signaled an error.
This causes two problems:
1. We pass back NULL to the caller via the contentp field,
but the function returns "0" for success. A caller
might reasonably expect after a successful return that
it can access contentp without a NULL check and
segfault.
As it happens, this is impossible to trigger in the
current code. There is exactly one caller which uses
contentp, read_object(). And the only thing it does
after a successful call is to return the content
pointer to its caller, using NULL as a sentinel for
errors. So in effect it converts the success code from
sha1_object_info_extended() back into an error!
But this is still worth addressing avoid problems for
future users of "contentp".
2. Callers of unpack_sha1_rest() are expected to close the
zlib stream themselves on error. Which means that we're
leaking the stream.
The problem in (1) comes from from c84a1f3ed4 (sha1_file:
refactor read_object, 2017-06-21), which added the contentp
field. Before that, we called unpack_sha1_rest() via
unpack_sha1_file(), which directly used the NULL to signal
an error.
But note that the leak in (2) is actually older than that.
The original unpack_sha1_file() directly returned the result
of unpack_sha1_rest() to its caller, when it should have
been closing the zlib stream itself on error.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Code clean-up to prevent future mistakes by copying and pasting
code that checks the result of read_in_full() function.
* jk/read-in-full:
worktree: check the result of read_in_full()
worktree: use xsize_t to access file size
distinguish error versus short read from read_in_full()
avoid looking at errno for short read_in_full() returns
prefer "!=" when checking read_in_full() result
notes-merge: drop dead zero-write code
files-backend: prefer "0" for write_in_full() error check
When a caller tries to read a particular set of bytes via
read_in_full(), there are three possible outcomes:
1. An error, in which case -1 is returned and errno is
set.
2. A short read, in which fewer bytes are returned and
errno is unspecified (we never saw a read error, so we
may have some random value from whatever syscall failed
last).
3. The full read completed successfully.
Many callers handle cases 1 and 2 together by just checking
the result against the requested size. If their combined
error path looks at errno (e.g., by calling die_errno), they
may report a nonsense value.
Let's fix these sites by having them distinguish between the
two error cases. That avoids the random errno confusion, and
lets us give more detailed error messages.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A regression fix for 2.11 that made the code to read the list of
alternate object stores overrun the end of the string.
* jk/info-alternates-fix:
read_info_alternates: warn on non-trivial errors
read_info_alternates: read contents into strbuf
Many codepaths did not diagnose write failures correctly when disks
go full, due to their misuse of write_in_full() helper function,
which have been corrected.
* jk/write-in-full-fix:
read_pack_header: handle signed/unsigned comparison in read result
config: flip return value of store_write_*()
notes-merge: use ssize_t for write_in_full() return value
pkt-line: check write_in_full() errors against "< 0"
convert less-trivial versions of "write_in_full() != len"
avoid "write_in_full(fd, buf, len) != len" pattern
get-tar-commit-id: check write_in_full() return against 0
config: avoid "write_in_full(fd, buf, len) < len" pattern
When we fail to open $GIT_DIR/info/alternates, we silently
assume there are no alternates. This is the right thing to
do for ENOENT, but not for other errors.
A hard error is probably overkill here. If we fail to read
an alternates file then either we'll complete our operation
anyway, or we'll fail to find some needed object. Either
way, a warning is good idea. And we already have a helper
function to handle this pattern; let's just call
warn_on_fopen_error().
Note that technically the errno from strbuf_read_file()
might be from a read() error, not open(). But since read()
would never return ENOENT or ENOTDIR, and since it produces
a generic "unable to access" error, it's suitable for
handling errors from either.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This patch fixes a regression in v2.11.1 where we might read
past the end of an mmap'd buffer. It was introduced in
cf3c635210.
The link_alt_odb_entries() function has always taken a
ptr/len pair as input. Until cf3c635210 (alternates: accept
double-quoted paths, 2016-12-12), we made a copy of those
bytes in a string. But after that commit, we switched to
parsing the input left-to-right, and we ignore "len"
totally, instead reading until we hit a NUL.
This has mostly gone unnoticed for a few reasons:
1. All but one caller passes a NUL-terminated string, with
"len" pointing to the NUL.
2. The remaining caller, read_info_alternates(), passes in
an mmap'd file. Unless the file is an exact multiple of
the page size, it will generally be followed by NUL
padding to the end of the page, which just works.
The easiest way to demonstrate the problem is to build with:
make SANITIZE=address NO_MMAP=Nope test
Any test which involves $GIT_DIR/info/alternates will fail,
as the mmap emulation (correctly) does not add an extra NUL,
and ASAN complains about reading past the end of the buffer.
One solution would be to teach link_alt_odb_entries() to
respect "len". But it's actually a bit tricky, since we
depend on unquote_c_style() under the hood, and it has no
ptr/len variant.
We could also just make a NUL-terminated copy of the input
bytes and operate on that. But since all but one caller
already is passing a string, instead let's just fix that
caller to provide NUL-terminated input in the first place,
by swapping out mmap for strbuf_read_file().
There's no advantage to using mmap on the alternates file.
It's not expected to be large (and anyway, we're copying its
contents into an in-memory linked list). Nor is using
git_open() buying us anything here, since we don't keep the
descriptor open for a long period of time.
Let's also drop the "len" parameter entirely from
link_alt_odb_entries(), since it's completely ignored. That
will avoid any new callers re-introducing a similar bug.
Reported-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Many leaks of strbuf have been fixed.
* rs/strbuf-leakfix: (34 commits)
wt-status: release strbuf after use in wt_longstatus_print_tracking()
wt-status: release strbuf after use in read_rebase_todolist()
vcs-svn: release strbuf after use in end_revision()
utf8: release strbuf on error return in strbuf_utf8_replace()
userdiff: release strbuf after use in userdiff_get_textconv()
transport-helper: release strbuf after use in process_connect_service()
sequencer: release strbuf after use in save_head()
shortlog: release strbuf after use in insert_one_record()
sha1_file: release strbuf on error return in index_path()
send-pack: release strbuf on error return in send_pack()
remote: release strbuf after use in set_url()
remote: release strbuf after use in migrate_file()
remote: release strbuf after use in read_remote_branches()
refs: release strbuf on error return in write_pseudoref()
notes: release strbuf after use in notes_copy_from_stdin()
merge: release strbuf after use in write_merge_heads()
merge: release strbuf after use in save_state()
mailinfo: release strbuf on error return in handle_boundary()
mailinfo: release strbuf after use in handle_from()
help: release strbuf on error return in exec_woman_emacs()
...
The result of read_in_full() may be -1 if we saw an error.
But in comparing it to a sizeof() result, that "-1" will be
promoted to size_t. In fact, the largest possible size_t
which is much bigger than our struct size. This means that
our "< sizeof(header)" error check won't trigger.
In practice, we'd go on to read uninitialized memory and
compare it to the PACK signature, which is likely to fail.
But we shouldn't get there.
We can fix this by making a direct "!=" comparison to the
requested size, rather than "<". This means that errors get
lumped in with short reads, but that's sufficient for our
purposes here. There's no PH_ERROR tp represent our case.
And anyway, this function reads from pipes and network
sockets. A network error may racily appear as EOF to us
anyway if there's data left in the socket buffers.
Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
strbuf_readlink() already frees the buffer for us on error. Clean up
if write_sha1_file() fails as well instead of returning early.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Conversion from uchar[20] to struct object_id continues; this is to
ensure that we do not assume sizeof(struct object_id) is the same
as the length of SHA-1 hash (or length of longest hash we support).
* po/read-graft-line:
commit: rewrite read_graft_line
commit: allocate array using object_id size
commit: replace the raw buffer with strbuf in read_graft_line
sha1_file: fix definition of null_sha1
This function needs to be global as it is used by sha1_file.c and will
be used by packfile.c.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Both sha1_file.c and packfile.c now need read_object(), so a copy of
read_object() was created in packfile.c.
This patch makes both mark_bad_packed_object() and has_packed_and_bad()
global. Unlike most of the other patches in this series, these 2
functions need to remain global.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The function open_packed_git() needs to be temporarily made global. Its
scope will be restored to static in a subsequent commit.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The function close_pack_fd() needs to be temporarily made global. Its
scope will be restored to static in a subsequent commit.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The function unuse_one_window() needs to be temporarily made global. Its
scope will be restored to static in a subsequent commit.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
alloc_packed_git() in packfile.c is duplicated from sha1_file.c. In a
subsequent commit, alloc_packed_git() will be removed from sha1_file.c.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_file.c declares some static variables that store packfile-related
state. Move them to packfile.c.
They are temporarily made global, but subsequent commits will restore
their scope back to static.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Currently, sha1_file.c and cache.h contain many functions, both related
to and unrelated to packfiles. This makes both files very large and
causes an unclear separation of concerns.
Create a new file, packfile.c, to hold all packfile-related functions
currently in sha1_file.c. It has a corresponding header packfile.h.
In this commit, the pack name-related functions are moved. Subsequent
commits will move the other functions.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
