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authorEric Biggers <ebiggers@google.com>2020-08-11 18:35:24 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-08-19 08:16:28 +0200
commita5305f119907ddcd5100b81264af43b930700c66 (patch)
treeaad76ddf16d1ae301f0db2aa19b3ad89e8725699
parent5be9072b8121b578b1429a35d5b158d55583e043 (diff)
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fs/minix: check return value of sb_getblk()
commit da27e0a0e5f655f0d58d4e153c3182bb2b290f64 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/minix/itree_common.c8
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,