| Message ID | 1395321596-4096-1-git-send-email-luis.henriques@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 5959b80..079005a 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -151,9 +151,8 @@ static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) static inline unsigned int unix_hash_fold(__wsum n) { - unsigned int hash = (__force unsigned int)n; + unsigned int hash = (__force unsigned int)csum_fold(n); - hash ^= hash>>16; hash ^= hash>>8; return hash&(UNIX_HASH_SIZE-1); }
This is a note to let you know that I have just added a patch titled net: unix socket code abuses csum_partial to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From a02019caab09e0d9059e2c31facce6e43112b806 Mon Sep 17 00:00:00 2001 From: Anton Blanchard <anton@samba.org> Date: Wed, 5 Mar 2014 14:29:58 +1100 Subject: net: unix socket code abuses csum_partial commit 0a13404dd3bf4ea870e3d96270b5a382edca85c0 upstream. The unix socket code is using the result of csum_partial to hash into a lookup table: unix_hash_fold(csum_partial(sunaddr, len, 0)); csum_partial is only guaranteed to produce something that can be folded into a checksum, as its prototype explains: * returns a 32-bit number suitable for feeding into itself * or csum_tcpudp_magic The 32bit value should not be used directly. Depending on the alignment, the ppc64 csum_partial will return different 32bit partial checksums that will fold into the same 16bit checksum. This difference causes the following testcase (courtesy of Gustavo) to sometimes fail: #include <sys/socket.h> #include <stdio.h> int main() { int fd = socket(PF_LOCAL, SOCK_STREAM|SOCK_CLOEXEC, 0); int i = 1; setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &i, 4); struct sockaddr addr; addr.sa_family = AF_LOCAL; bind(fd, &addr, 2); listen(fd, 128); struct sockaddr_storage ss; socklen_t sslen = (socklen_t)sizeof(ss); getsockname(fd, (struct sockaddr*)&ss, &sslen); fd = socket(PF_LOCAL, SOCK_STREAM|SOCK_CLOEXEC, 0); if (connect(fd, (struct sockaddr*)&ss, sslen) == -1){ perror(NULL); return 1; } printf("OK\n"); return 0; } As suggested by davem, fix this by using csum_fold to fold the partial 32bit checksum into a 16bit checksum before using it. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- net/unix/af_unix.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) -- 1.9.1