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author | Dan Carpenter <dan.carpenter@oracle.com> | 2018-09-06 12:47:51 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-26 09:33:58 +0300 |
commit | cece1875d935c58d9dd6a2733be852948d5e1b6d (patch) | |
tree | de3cdf36fe70310f023c59730e7d567ec3c71978 /fs/cifs | |
parent | 6f3e0e8ac116f2a88e2d21d4e66e1aaa8bc59e75 (diff) | |
download | linux-cece1875d935c58d9dd6a2733be852948d5e1b6d.tar.xz |
cifs: prevent integer overflow in nxt_dir_entry()
commit 8ad8aa353524d89fa2e09522f3078166ff78ec42 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/cifs')
-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 404b084614aa..707d8cf95348 100644 --- a/fs/cifs/readdir.c +++ b/fs/cifs/readdir.c @@ -366,8 +366,15 @@ 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) { |