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| author | Eric Biggers <ebiggers@google.com> | 2020-08-11 18:35:24 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-12 10:58:00 -0700 |
| commit | da27e0a0e5f655f0d58d4e153c3182bb2b290f64 (patch) | |
| tree | 22150b2eb3f869f6e5f1df84dda39522d1089c6e /fs | |
| parent | 2fb3244f0a58ceb3d866ac63f644dfa31cae430f (diff) | |
| download | linux-da27e0a0e5f655f0d58d4e153c3182bb2b290f64.tar.bz2 | |
fs/minix: check return value of sb_getblk()
Patch series "fs/minix: fix syzbot bugs and set s_maxbytes".
This series fixes all syzbot bugs in the minix filesystem:
KASAN: null-ptr-deref Write in get_block
KASAN: use-after-free Write in get_block
KASAN: use-after-free Read in get_block
WARNING in inc_nlink
KMSAN: uninit-value in get_block
WARNING in drop_nlink
It also fixes the minix filesystem to set s_maxbytes correctly, so that
userspace sees the correct behavior when exceeding the max file size.
This patch (of 6):
sb_getblk() can fail, so check its return value.
This fixes a NULL pointer dereference.
Originally from Qiujun Huang.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+4a88b2b9dc280f47baf4@syzkaller.appspotmail.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Qiujun Huang <anenbupt@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200628060846.682158-1-ebiggers@kernel.org
Link: http://lkml.kernel.org/r/20200628060846.682158-2-ebiggers@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/minix/itree_common.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/fs/minix/itree_common.c b/fs/minix/itree_common.c index 043c3fdbc8e7..446148792f41 100644 --- a/fs/minix/itree_common.c +++ b/fs/minix/itree_common.c @@ -75,6 +75,7 @@ static int alloc_branch(struct inode *inode, int n = 0; int i; int parent = minix_new_block(inode); + int err = -ENOSPC; branch[0].key = cpu_to_block(parent); if (parent) for (n = 1; n < num; n++) { @@ -85,6 +86,11 @@ static int alloc_branch(struct inode *inode, break; branch[n].key = cpu_to_block(nr); bh = sb_getblk(inode->i_sb, parent); + if (!bh) { + minix_free_block(inode, nr); + err = -ENOMEM; + break; + } lock_buffer(bh); memset(bh->b_data, 0, bh->b_size); branch[n].bh = bh; @@ -103,7 +109,7 @@ static int alloc_branch(struct inode *inode, bforget(branch[i].bh); for (i = 0; i < n; i++) minix_free_block(inode, block_to_cpu(branch[i].key)); - return -ENOSPC; + return err; } static inline int splice_branch(struct inode *inode, |