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| author | Dan Carpenter <dan.carpenter@oracle.com> | 2018-09-06 12:47:51 +0300 |
|---|---|---|
| committer | Steve French <stfrench@microsoft.com> | 2018-09-12 09:27:57 -0500 |
| commit | 8ad8aa353524d89fa2e09522f3078166ff78ec42 (patch) | |
| tree | c95029b8a3efc9cdfbb70b9d666812c44ff18b17 /fs/cifs/readdir.c | |
| parent | 5890184d2b506f88886b7322d7d44464453bd3a6 (diff) | |
| download | linux-8ad8aa353524d89fa2e09522f3078166ff78ec42.tar.gz linux-8ad8aa353524d89fa2e09522f3078166ff78ec42.tar.bz2 linux-8ad8aa353524d89fa2e09522f3078166ff78ec42.zip | |
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/cifs/readdir.c')
| -rw-r--r-- | fs/cifs/readdir.c | 11 |
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) { |