From: Daniel Borkmann <dborkman@xxxxxxxxxx>
This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.
===============
[ Upstream commit ff5e92c1affe7166b3f6e7073e648ed65a6e2e59 ]
sysctl handler proc_sctp_do_hmac_alg(), proc_sctp_do_rto_min() and
proc_sctp_do_rto_max() do not properly reflect some error cases
when writing values via sysctl from internal proc functions such
as proc_dointvec() and proc_dostring().
In all these cases we pass the test for write != 0 and partially
do additional work just to notice that additional sanity checks
fail and we return with hard-coded -EINVAL while proc_do*
functions might also return different errors. So fix this up by
simply testing a successful return of proc_do* right after
calling it.
This also allows to propagate its return value onwards to the user.
While touching this, also fix up some minor style issues.
Fixes: 4f3fdf3bc59c ("sctp: add check rto_min and rto_max in sysctl")
Fixes: 3c68198e7511 ("sctp: Make hmac algorithm selection for cookie generation dynamic")
Signed-off-by: Daniel Borkmann <dborkman@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
net/sctp/sysctl.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 3e5ac1948607..976c89d5295b 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -303,41 +303,40 @@ static int proc_sctp_do_hmac_alg(struct ctl_table *ctl,
loff_t *ppos)
{
struct net *net = current->nsproxy->net_ns;
- char tmp[8];
struct ctl_table tbl;
- int ret;
- int changed = 0;
+ bool changed = false;
char *none = "none";
+ char tmp[8];
+ int ret;
memset(&tbl, 0, sizeof(struct ctl_table));
if (write) {
tbl.data = tmp;
- tbl.maxlen = 8;
+ tbl.maxlen = sizeof(tmp);
} else {
tbl.data = net->sctp.sctp_hmac_alg ? : none;
tbl.maxlen = strlen(tbl.data);
}
- ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
- if (write) {
+ ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
+ if (write && ret == 0) {
#ifdef CONFIG_CRYPTO_MD5
if (!strncmp(tmp, "md5", 3)) {
net->sctp.sctp_hmac_alg = "md5";
- changed = 1;
+ changed = true;
}
#endif
#ifdef CONFIG_CRYPTO_SHA1
if (!strncmp(tmp, "sha1", 4)) {
net->sctp.sctp_hmac_alg = "sha1";
- changed = 1;
+ changed = true;
}
#endif
if (!strncmp(tmp, "none", 4)) {
net->sctp.sctp_hmac_alg = NULL;
- changed = 1;
+ changed = true;
}
-
if (!changed)
ret = -EINVAL;
}
--
2.0.1
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