linux/fs/isofs/namei.c
Kees Cook 3f649ab728 treewide: Remove uninitialized_var() usage
Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB
Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers
Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-07-16 12:35:15 -07:00

174 lines
4.1 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/isofs/namei.c
*
* (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem.
*
* (C) 1991 Linus Torvalds - minix filesystem
*/
#include <linux/gfp.h>
#include "isofs.h"
/*
* ok, we cannot use strncmp, as the name is not in our data space.
* Thus we'll have to use isofs_match. No big problem. Match also makes
* some sanity tests.
*/
static int
isofs_cmp(struct dentry *dentry, const char *compare, int dlen)
{
struct qstr qstr;
qstr.name = compare;
qstr.len = dlen;
if (likely(!dentry->d_op))
return dentry->d_name.len != dlen || memcmp(dentry->d_name.name, compare, dlen);
return dentry->d_op->d_compare(NULL, dentry->d_name.len, dentry->d_name.name, &qstr);
}
/*
* isofs_find_entry()
*
* finds an entry in the specified directory with the wanted name. It
* returns the inode number of the found entry, or 0 on error.
*/
static unsigned long
isofs_find_entry(struct inode *dir, struct dentry *dentry,
unsigned long *block_rv, unsigned long *offset_rv,
char *tmpname, struct iso_directory_record *tmpde)
{
unsigned long bufsize = ISOFS_BUFFER_SIZE(dir);
unsigned char bufbits = ISOFS_BUFFER_BITS(dir);
unsigned long block, f_pos, offset, block_saved, offset_saved;
struct buffer_head *bh = NULL;
struct isofs_sb_info *sbi = ISOFS_SB(dir->i_sb);
if (!ISOFS_I(dir)->i_first_extent)
return 0;
f_pos = 0;
offset = 0;
block = 0;
while (f_pos < dir->i_size) {
struct iso_directory_record *de;
int de_len, match, i, dlen;
char *dpnt;
if (!bh) {
bh = isofs_bread(dir, block);
if (!bh)
return 0;
}
de = (struct iso_directory_record *) (bh->b_data + offset);
de_len = *(unsigned char *) de;
if (!de_len) {
brelse(bh);
bh = NULL;
f_pos = (f_pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
block = f_pos >> bufbits;
offset = 0;
continue;
}
block_saved = bh->b_blocknr;
offset_saved = offset;
offset += de_len;
f_pos += de_len;
/* Make sure we have a full directory entry */
if (offset >= bufsize) {
int slop = bufsize - offset + de_len;
memcpy(tmpde, de, slop);
offset &= bufsize - 1;
block++;
brelse(bh);
bh = NULL;
if (offset) {
bh = isofs_bread(dir, block);
if (!bh)
return 0;
memcpy((void *) tmpde + slop, bh->b_data, offset);
}
de = tmpde;
}
dlen = de->name_len[0];
dpnt = de->name;
/* Basic sanity check, whether name doesn't exceed dir entry */
if (de_len < dlen + sizeof(struct iso_directory_record)) {
printk(KERN_NOTICE "iso9660: Corrupted directory entry"
" in block %lu of inode %lu\n", block,
dir->i_ino);
return 0;
}
if (sbi->s_rock &&
((i = get_rock_ridge_filename(de, tmpname, dir)))) {
dlen = i; /* possibly -1 */
dpnt = tmpname;
#ifdef CONFIG_JOLIET
} else if (sbi->s_joliet_level) {
dlen = get_joliet_filename(de, tmpname, dir);
dpnt = tmpname;
#endif
} else if (sbi->s_mapping == 'a') {
dlen = get_acorn_filename(de, tmpname, dir);
dpnt = tmpname;
} else if (sbi->s_mapping == 'n') {
dlen = isofs_name_translate(de, tmpname, dir);
dpnt = tmpname;
}
/*
* Skip hidden or associated files unless hide or showassoc,
* respectively, is set
*/
match = 0;
if (dlen > 0 &&
(!sbi->s_hide ||
(!(de->flags[-sbi->s_high_sierra] & 1))) &&
(sbi->s_showassoc ||
(!(de->flags[-sbi->s_high_sierra] & 4)))) {
if (dpnt && (dlen > 1 || dpnt[0] > 1))
match = (isofs_cmp(dentry, dpnt, dlen) == 0);
}
if (match) {
isofs_normalize_block_and_offset(de,
&block_saved,
&offset_saved);
*block_rv = block_saved;
*offset_rv = offset_saved;
brelse(bh);
return 1;
}
}
brelse(bh);
return 0;
}
struct dentry *isofs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
int found;
unsigned long block;
unsigned long offset;
struct inode *inode;
struct page *page;
page = alloc_page(GFP_USER);
if (!page)
return ERR_PTR(-ENOMEM);
found = isofs_find_entry(dir, dentry,
&block, &offset,
page_address(page),
1024 + page_address(page));
__free_page(page);
inode = found ? isofs_iget(dir->i_sb, block, offset) : NULL;
return d_splice_alias(inode, dentry);
}