Messages in this thread Patch in this message | | | Date | Thu, 07 Jun 2012 13:04:35 +0900 | From | Greg KH <> | Subject | [ 59/82] ext4: fix potential NULL dereference in ext4_free_inodes_counts() |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Dan Carpenter <dan.carpenter@oracle.com>
commit bb3d132a24cd8bf5e7773b2d9f9baa58b07a7dae upstream.
The ext4_get_group_desc() function returns NULL on error, and ext4_free_inodes_count() function dereferences it without checking. There is a check on the next line, but it's too late.
Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/ext4/ialloc.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
--- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -488,10 +488,12 @@ fallback_retry: for (i = 0; i < ngroups; i++) { grp = (parent_group + i) % ngroups; desc = ext4_get_group_desc(sb, grp, NULL); - grp_free = ext4_free_inodes_count(sb, desc); - if (desc && grp_free && grp_free >= avefreei) { - *group = grp; - return 0; + if (desc) { + grp_free = ext4_free_inodes_count(sb, desc); + if (grp_free && grp_free >= avefreei) { + *group = grp; + return 0; + } } }
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