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authorDan Carpenter <dan.carpenter@oracle.com>2018-09-06 12:47:51 +0300
committerSteve French <stfrench@microsoft.com>2018-09-12 17:27:57 +0300
commit8ad8aa353524d89fa2e09522f3078166ff78ec42 (patch)
treec95029b8a3efc9cdfbb70b9d666812c44ff18b17 /fs
parent5890184d2b506f88886b7322d7d44464453bd3a6 (diff)
downloadlinux-8ad8aa353524d89fa2e09522f3078166ff78ec42.tar.xz
cifs: prevent integer overflow in nxt_dir_entry()
The "old_entry + le32_to_cpu(pDirInfo->NextEntryOffset)" can wrap around so I have added a check for integer overflow. Reported-by: Dr Silvio Cesare of InfoSect <silvio.cesare@gmail.com> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Steve French <stfrench@microsoft.com> CC: Stable <stable@vger.kernel.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/cifs/readdir.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index eeab81c9452f..e169e1a5fd35 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -376,8 +376,15 @@ static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
pfData->FileNameLength;
- } else
- new_entry = old_entry + le32_to_cpu(pDirInfo->NextEntryOffset);
+ } else {
+ u32 next_offset = le32_to_cpu(pDirInfo->NextEntryOffset);
+
+ if (old_entry + next_offset < old_entry) {
+ cifs_dbg(VFS, "invalid offset %u\n", next_offset);
+ return NULL;
+ }
+ new_entry = old_entry + next_offset;
+ }
cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
/* validate that new_entry is not past end of SMB */
if (new_entry >= end_of_smb) {