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Date: Thu, 19 Jun 2014 01:31:30 +0200
From: Daniel Borkmann <dborkman@...hat.com>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, linux-sctp@...r.kernel.org
Subject: [PATCH net] net: sctp: propagate sysctl errors from proc_do* properly
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@...hat.com>
---
net/sctp/sysctl.c | 43 +++++++++++++++++++++++--------------------
1 file changed, 23 insertions(+), 20 deletions(-)
diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 8a5b5c2..12c7e01 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -321,41 +321,40 @@ static int proc_sctp_do_hmac_alg(struct ctl_table *ctl, int write,
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;
}
@@ -368,11 +367,10 @@ static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
loff_t *ppos)
{
struct net *net = current->nsproxy->net_ns;
- int new_value;
- struct ctl_table tbl;
unsigned int min = *(unsigned int *) ctl->extra1;
unsigned int max = *(unsigned int *) ctl->extra2;
- int ret;
+ struct ctl_table tbl;
+ int ret, new_value;
memset(&tbl, 0, sizeof(struct ctl_table));
tbl.maxlen = sizeof(unsigned int);
@@ -381,12 +379,15 @@ static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
tbl.data = &new_value;
else
tbl.data = &net->sctp.rto_min;
+
ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
- if (write) {
- if (ret || new_value > max || new_value < min)
+ if (write && ret == 0) {
+ if (new_value > max || new_value < min)
return -EINVAL;
+
net->sctp.rto_min = new_value;
}
+
return ret;
}
@@ -395,11 +396,10 @@ static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
loff_t *ppos)
{
struct net *net = current->nsproxy->net_ns;
- int new_value;
- struct ctl_table tbl;
unsigned int min = *(unsigned int *) ctl->extra1;
unsigned int max = *(unsigned int *) ctl->extra2;
- int ret;
+ struct ctl_table tbl;
+ int ret, new_value;
memset(&tbl, 0, sizeof(struct ctl_table));
tbl.maxlen = sizeof(unsigned int);
@@ -408,12 +408,15 @@ static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
tbl.data = &new_value;
else
tbl.data = &net->sctp.rto_max;
+
ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
- if (write) {
- if (ret || new_value > max || new_value < min)
+ if (write && ret == 0) {
+ if (new_value > max || new_value < min)
return -EINVAL;
+
net->sctp.rto_max = new_value;
}
+
return ret;
}
--
1.7.11.7
--
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