lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Sun, 06 Jan 2013 20:21:49 -0800 From: Eric Dumazet <eric.dumazet@...il.com> To: Willy Tarreau <w@....eu>, David Miller <davem@...emloft.net> Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org Subject: [PATCH] tcp: fix MSG_SENDPAGE_NOTLAST logic From: Eric Dumazet <edumazet@...gle.com> commit 35f9c09fe9c72e (tcp: tcp_sendpages() should call tcp_push() once) added an internal flag : MSG_SENDPAGE_NOTLAST meant to be set on all frags but the last one for a splice() call. The condition used to set the flag in pipe_to_sendpage() relied on splice() user passing the exact number of bytes present in the pipe, or a smaller one. But some programs pass an arbitrary high value, and the test fails. The effect of this bug is a lack of tcp_push() at the end of a splice(pipe -> socket) call, and possibly very slow or erratic TCP sessions. We should both test sd->total_len and fact that another fragment is in the pipe (pipe->nrbufs > 1) Many thanks to Willy for providing very clear bug report, bisection and test programs. Reported-by: Willy Tarreau <w@....eu> Bisected-by: Willy Tarreau <w@....eu> Tested-by: Willy Tarreau <w@....eu> Signed-off-by: Eric Dumazet <edumazet@...gle.com> --- fs/splice.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/splice.c b/fs/splice.c index 8890604..6909d89 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -696,8 +696,10 @@ static int pipe_to_sendpage(struct pipe_inode_info *pipe, return -EINVAL; more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0; - if (sd->len < sd->total_len) + + if (sd->len < sd->total_len && pipe->nrbufs > 1) more |= MSG_SENDPAGE_NOTLAST; + return file->f_op->sendpage(file, buf->page, buf->offset, sd->len, &pos, more); } -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists