diff options
| author | Robin Holt <holt@sgi.com> | 2010-10-20 02:03:37 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-12-09 13:27:06 -0800 |
| commit | 61690148345a4a1ccced61ad9c44862f74d947cf (patch) | |
| tree | efe8e4a48973e19e2a0ae5670be0ad330b504fa8 /net/ipv4 | |
| parent | 1b881c33e3d1afde2324ee9c324a0463b0e8df8b (diff) | |
Limit sysctl_tcp_mem and sysctl_udp_mem initializers to prevent integer overflows.
[ Upstream fixed this in a different way as parts of the commits:
8d987e5c7510 (net: avoid limits overflow)
a9febbb4bd13 (sysctl: min/max bounds are optional)
27b3d80a7b6a (sysctl: fix min/max handling in __do_proc_doulongvec_minmax())
-DaveM ]
On a 16TB x86_64 machine, sysctl_tcp_mem[2], sysctl_udp_mem[2], and
sysctl_sctp_mem[2] can integer overflow. Set limit such that they are
maximized without overflowing.
Signed-off-by: Robin Holt <holt@sgi.com>
To: "David S. Miller" <davem@davemloft.net>
Cc: Willy Tarreau <w@1wt.eu>
Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-sctp@vger.kernel.org
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: "Pekka Savola (ipv6)" <pekkas@netcore.fi>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Vlad Yasevich <vladislav.yasevich@hp.com>
Cc: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/tcp.c | 4 | ||||
| -rw-r--r-- | net/ipv4/udp.c | 4 |
2 files changed, 6 insertions, 2 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 46783087137..734fe94827d 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2940,12 +2940,14 @@ void __init tcp_init(void) /* Set the pressure threshold to be a fraction of global memory that * is up to 1/2 at 256 MB, decreasing toward zero with the amount of - * memory, with a floor of 128 pages. + * memory, with a floor of 128 pages, and a ceiling that prevents an + * integer overflow. */ nr_pages = totalram_pages - totalhigh_pages; limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT); limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11); limit = max(limit, 128UL); + limit = min(limit, INT_MAX * 4UL / 3 / 2); sysctl_tcp_mem[0] = limit / 4 * 3; sysctl_tcp_mem[1] = limit; sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index c322f4429fc..31db78ca746 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1832,12 +1832,14 @@ void __init udp_init(void) udp_table_init(&udp_table); /* Set the pressure threshold up by the same strategy of TCP. It is a * fraction of global memory that is up to 1/2 at 256 MB, decreasing - * toward zero with the amount of memory, with a floor of 128 pages. + * toward zero with the amount of memory, with a floor of 128 pages, + * and a ceiling that prevents an integer overflow. */ nr_pages = totalram_pages - totalhigh_pages; limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT); limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11); limit = max(limit, 128UL); + limit = min(limit, INT_MAX * 4UL / 3 / 2); sysctl_udp_mem[0] = limit / 4 * 3; sysctl_udp_mem[1] = limit; sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2; |