Re: [PATCH] jfs: fix array-index-out-of-bounds in diNewExt

From: Dave Kleikamp
Date: Tue Jan 02 2024 - 12:11:06 EST

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On 1/2/24 7:29AM, Dan Carpenter wrote:

Hi Edward,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Edward-Adam-Davis/jfs-fix-array-index-out-of-bounds-in-diNewExt/20231212-095530
base: https://github.com/kleikamp/linux-shaggy jfs-next
patch link: https://lore.kernel.org/r/tencent_B86ECD2ECECC92A7ED86EF92D0064A499206%40qq.com
patch subject: [PATCH] jfs: fix array-index-out-of-bounds in diNewExt
config: i386-randconfig-141-20231212 (https://download.01.org/0day-ci/archive/20231214/202312142348.6HRZtXTB-lkp@xxxxxxxxx/config)
compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0
reproduce: (https://download.01.org/0day-ci/archive/20231214/202312142348.6HRZtXTB-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
| Closes: https://lore.kernel.org/r/202312142348.6HRZtXTB-lkp@xxxxxxxxx/

I modified Edward's patch in the jfs-next branch with the corrected test.

Thanks for catching this.

Shaggy

New smatch warnings:
fs/jfs/jfs_imap.c:2213 diNewExt() error: buffer overflow 'imap->im_imap.in_agctl' 128 <= 128

Old smatch warnings:
fs/jfs/jfs_imap.c:2229 diNewExt() error: buffer overflow 'imap->im_imap.in_agctl' 128 <= 128
fs/jfs/jfs_imap.c:2304 diNewExt() error: buffer overflow 'imap->im_imap.in_agctl' 128 <= 128
fs/jfs/jfs_imap.c:2318 diNewExt() error: buffer overflow 'imap->im_imap.in_agctl' 128 <= 128
fs/jfs/jfs_imap.c:2330 diNewExt() error: buffer overflow 'imap->im_imap.in_agctl' 128 <= 128
fs/jfs/jfs_imap.c:2332 diNewExt() error: buffer overflow 'imap->im_imap.in_agctl' 128 <= 128
fs/jfs/jfs_imap.c:2363 diNewExt() error: buffer overflow 'imap->im_imap.in_agctl' 128 <= 128
fs/jfs/jfs_imap.c:2364 diNewExt() error: buffer overflow 'imap->im_imap.in_agctl' 128 <= 128

vim +2213 fs/jfs/jfs_imap.c

^1da177e4c3f41 Linus Torvalds 2005-04-16 2152 static int diNewExt(struct inomap * imap, struct iag * iagp, int extno)
^1da177e4c3f41 Linus Torvalds 2005-04-16 2153 {
^1da177e4c3f41 Linus Torvalds 2005-04-16 2154 int agno, iagno, fwd, back, freei = 0, sword, rc;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2155 struct iag *aiagp = NULL, *biagp = NULL, *ciagp = NULL;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2156 struct metapage *amp, *bmp, *cmp, *dmp;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2157 struct inode *ipimap;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2158 s64 blkno, hint;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2159 int i, j;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2160 u32 mask;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2161 ino_t ino;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2162 struct dinode *dp;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2163 struct jfs_sb_info *sbi;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2164
^1da177e4c3f41 Linus Torvalds 2005-04-16 2165 /* better have free extents.
^1da177e4c3f41 Linus Torvalds 2005-04-16 2166 */
^1da177e4c3f41 Linus Torvalds 2005-04-16 2167 if (!iagp->nfreeexts) {
eb8630d7d2fd13 Joe Perches 2013-06-04 2168 jfs_error(imap->im_ipimap->i_sb, "no free extents\n");
^1da177e4c3f41 Linus Torvalds 2005-04-16 2169 return -EIO;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2170 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 2171
^1da177e4c3f41 Linus Torvalds 2005-04-16 2172 /* get the inode map inode.
^1da177e4c3f41 Linus Torvalds 2005-04-16 2173 */
^1da177e4c3f41 Linus Torvalds 2005-04-16 2174 ipimap = imap->im_ipimap;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2175 sbi = JFS_SBI(ipimap->i_sb);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2176
^1da177e4c3f41 Linus Torvalds 2005-04-16 2177 amp = bmp = cmp = NULL;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2178
^1da177e4c3f41 Linus Torvalds 2005-04-16 2179 /* get the ag and iag numbers for this iag.
^1da177e4c3f41 Linus Torvalds 2005-04-16 2180 */
^1da177e4c3f41 Linus Torvalds 2005-04-16 2181 agno = BLKTOAG(le64_to_cpu(iagp->agstart), sbi);
f93b91b82fcf16 Edward Adam Davis 2023-12-12 2182 if (agno > MAXAG || agno < 0)

The commit introduces this agno > MAXAG comparison. But Smatch says
that it should be agno >= MAXAG.

f93b91b82fcf16 Edward Adam Davis 2023-12-12 2183 return -EIO;
f93b91b82fcf16 Edward Adam Davis 2023-12-12 2184
^1da177e4c3f41 Linus Torvalds 2005-04-16 2185 iagno = le32_to_cpu(iagp->iagnum);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2186
^1da177e4c3f41 Linus Torvalds 2005-04-16 2187 /* check if this is the last free extent within the
^1da177e4c3f41 Linus Torvalds 2005-04-16 2188 * iag. if so, the iag must be removed from the ag
25985edcedea63 Lucas De Marchi 2011-03-30 2189 * free extent list, so get the iags preceding and
^1da177e4c3f41 Linus Torvalds 2005-04-16 2190 * following the iag on this list.
^1da177e4c3f41 Linus Torvalds 2005-04-16 2191 */
^1da177e4c3f41 Linus Torvalds 2005-04-16 2192 if (iagp->nfreeexts == cpu_to_le32(1)) {
^1da177e4c3f41 Linus Torvalds 2005-04-16 2193 if ((fwd = le32_to_cpu(iagp->extfreefwd)) >= 0) {
^1da177e4c3f41 Linus Torvalds 2005-04-16 2194 if ((rc = diIAGRead(imap, fwd, &amp)))
^1da177e4c3f41 Linus Torvalds 2005-04-16 2195 return (rc);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2196 aiagp = (struct iag *) amp->data;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2197 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 2198
^1da177e4c3f41 Linus Torvalds 2005-04-16 2199 if ((back = le32_to_cpu(iagp->extfreeback)) >= 0) {
^1da177e4c3f41 Linus Torvalds 2005-04-16 2200 if ((rc = diIAGRead(imap, back, &bmp)))
^1da177e4c3f41 Linus Torvalds 2005-04-16 2201 goto error_out;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2202 biagp = (struct iag *) bmp->data;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2203 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 2204 } else {
^1da177e4c3f41 Linus Torvalds 2005-04-16 2205 /* the iag has free extents. if all extents are free
^1da177e4c3f41 Linus Torvalds 2005-04-16 2206 * (as is the case for a newly allocated iag), the iag
^1da177e4c3f41 Linus Torvalds 2005-04-16 2207 * must be added to the ag free extent list, so get
^1da177e4c3f41 Linus Torvalds 2005-04-16 2208 * the iag at the head of the list in preparation for
^1da177e4c3f41 Linus Torvalds 2005-04-16 2209 * adding this iag to this list.
^1da177e4c3f41 Linus Torvalds 2005-04-16 2210 */
^1da177e4c3f41 Linus Torvalds 2005-04-16 2211 fwd = back = -1;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2212 if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG)) {
^1da177e4c3f41 Linus Torvalds 2005-04-16 @2213 if ((fwd = imap->im_agctl[agno].extfree) >= 0) {

If agno == MAXAG then we're out of bounds here.

^1da177e4c3f41 Linus Torvalds 2005-04-16 2214 if ((rc = diIAGRead(imap, fwd, &amp)))
^1da177e4c3f41 Linus Torvalds 2005-04-16 2215 goto error_out;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2216 aiagp = (struct iag *) amp->data;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2217 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 2218 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 2219 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 2220
^1da177e4c3f41 Linus Torvalds 2005-04-16 2221 /* check if the iag has no free inodes. if so, the iag

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In reply to: Dan Carpenter: "Re: [PATCH] jfs: fix array-index-out-of-bounds in diNewExt"
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