From: Jim Meyering <jim@meyering.net>
To: linux-kernel@vger.kernel.org
Cc: Jim Meyering <meyering@redhat.com>,
Steve French <sfrench@samba.org>,
linux-cifs@vger.kernel.org, samba-technical@lists.samba.org
Subject: [PATCH] cifs: remove misleading strncpy: each name has length < 16
Date: Mon, 20 Aug 2012 18:55:24 +0200 [thread overview]
Message-ID: <1345481724-30108-6-git-send-email-jim@meyering.net> (raw)
In-Reply-To: <1345481724-30108-1-git-send-email-jim@meyering.net>
From: Jim Meyering <meyering@redhat.com>
Each of the protocols[i].name strings (statically declared above)
has length less than 16, so this use of strncpy is misleading:
strncpy(pSMB->DialectsArray+count, protocols[i].name, 16);
Besides, if a new name were added with length N >= 16, the existing
strncpy-using code would be buggy, creating a ->DialectsArray buffer
containing N-16+1 unset bytes where the NUL terminator should have
been. Instead, traverse the name only once go get its length,
use a BUG_ON assertion to enforce the length restriction
and use memcpy to perform the copy.
Signed-off-by: Jim Meyering <meyering@redhat.com>
---
fs/cifs/cifssmb.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 074923c..16a9018 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -441,8 +441,10 @@ CIFSSMBNegotiate(const unsigned int xid, struct cifs_ses *ses)
count = 0;
for (i = 0; i < CIFS_NUM_PROT; i++) {
- strncpy(pSMB->DialectsArray+count, protocols[i].name, 16);
- count += strlen(protocols[i].name) + 1;
+ size_t len = strlen(protocols[i].name);
+ BUG_ON(len >= 16);
+ memcpy(pSMB->DialectsArray+count, protocols[i].name, len + 1);
+ count += len + 1;
/* null at end of source and target buffers anyway */
}
inc_rfc1001_len(pSMB, count);
--
1.7.12
next prev parent reply other threads:[~2012-08-20 17:29 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-20 16:55 a few strncpy-related patches Jim Meyering
2012-08-20 16:55 ` [PATCH] ACPI: remove unwarranted use of strncpy Jim Meyering
2012-08-20 16:55 ` [PATCH] fs/9p: avoid debug OOPS when reading a long symlink Jim Meyering
2012-08-21 7:20 ` [PATCHv2] " Jim Meyering
2012-08-20 16:55 ` [PATCH] kmemleak: avoid buffer overrun: NUL-terminate strncpy-copied command Jim Meyering
2012-08-24 10:27 ` Catalin Marinas
2012-08-24 11:23 ` Jim Meyering
2012-08-28 20:24 ` Dan Carpenter
2012-08-29 6:28 ` Jim Meyering
2012-08-29 15:56 ` Dan Carpenter
2012-08-20 16:55 ` [PATCH] bfa: avoid buffer overrun for 12-byte model name Jim Meyering
2012-08-20 19:42 ` Krishna Gudipati
2012-08-20 20:38 ` Jim Meyering
2012-10-14 7:53 ` Jim Meyering
2012-10-14 8:20 ` Jim Meyering
2012-12-24 7:43 ` Vijay Mohan Guvva
2012-08-20 16:55 ` Jim Meyering [this message]
[not found] ` <CAE2SPAbBmRov9qK2HiBQBQXaZpfJ8pmZJ-PL18FEyoZhzDza4A@mail.gmail.com>
2012-08-20 18:40 ` [PATCH] cifs: remove misleading strncpy: each name has length < 16 Jim Meyering
2012-08-20 18:41 ` Jim Meyering
2012-08-20 20:18 ` a few strncpy-related patches Andi Kleen
2012-08-20 20:47 ` Jim Meyering
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