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| author | Roman Gushchin <klamm@yandex-team.ru> | 2013-08-02 18:36:40 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-08-03 02:18:53 +0400 |
| commit | 5f671d6b4ec3e6d66c2a868738af2cdea09e7509 (patch) | |
| tree | b117717db9f3b70118095c0e12a0acb1daad5591 | |
| parent | 3508ea333ed5414561af4c818b3b80c0acca1845 (diff) | |
| download | linux-5f671d6b4ec3e6d66c2a868738af2cdea09e7509.tar.xz | |
net: check net.core.somaxconn sysctl values
It's possible to assign an invalid value to the net.core.somaxconn
sysctl variable, because there is no checks at all.
The sk_max_ack_backlog field of the sock structure is defined as
unsigned short. Therefore, the backlog argument in inet_listen()
shouldn't exceed USHRT_MAX. The backlog argument in the listen() syscall
is truncated to the somaxconn value. So, the somaxconn value shouldn't
exceed 65535 (USHRT_MAX).
Also, negative values of somaxconn are meaningless.
before:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
net.core.somaxconn = 65536
$ sysctl -w net.core.somaxconn=-100
net.core.somaxconn = -100
after:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
error: "Invalid argument" setting key "net.core.somaxconn"
$ sysctl -w net.core.somaxconn=-100
error: "Invalid argument" setting key "net.core.somaxconn"
Based on a prior patch from Changli Gao.
Signed-off-by: Roman Gushchin <klamm@yandex-team.ru>
Reported-by: Changli Gao <xiaosuo@gmail.com>
Suggested-by: Eric Dumazet <edumazet@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/core/sysctl_net_core.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index b59b6804fd98..31107abd2783 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -21,7 +21,9 @@ #include <net/net_ratelimit.h> #include <net/busy_poll.h> +static int zero = 0; static int one = 1; +static int ushort_max = USHRT_MAX; #ifdef CONFIG_RPS static int rps_sock_flow_sysctl(struct ctl_table *table, int write, @@ -339,7 +341,9 @@ static struct ctl_table netns_core_table[] = { .data = &init_net.core.sysctl_somaxconn, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec + .extra1 = &zero, + .extra2 = &ushort_max, + .proc_handler = proc_dointvec_minmax }, { } }; |