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Commit 620f6e8e authored by Kees Cook's avatar Kees Cook Committed by James Morris
Browse files

sysctl: fix write access to dmesg_restrict/kptr_restrict 

Commit bfdc0b49 adds code to restrict access to dmesg_restrict,
however, it incorrectly alters kptr_restrict rather than
dmesg_restrict.

The original patch from Richard Weinberger
(https://lkml.org/lkml/2011/3/14/362

) alters dmesg_restrict as
expected, and so the patch seems to have been misapplied.

This adds the CAP_SYS_ADMIN check to both dmesg_restrict and
kptr_restrict, since both are sensitive.

Reported-by: default avatarPhillip Lougher <plougher@redhat.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Acked-by: default avatarSerge Hallyn <serge.hallyn@canonical.com>
Acked-by: default avatarRichard Weinberger <richard@nod.at>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarJames Morris <james.l.morris@oracle.com>
parent 6c216ec6

kernel/sysctl.c

+4 −4
Original line number Diff line number Diff line
@@ -170,7 +170,7 @@ static int proc_taint(struct ctl_table *table, int write, 
#endif



#ifdef CONFIG_PRINTK

static int proc_dmesg_restrict(struct ctl_table *table, int write,

static int proc_dointvec_minmax_sysadmin(struct ctl_table *table, int write,

				void __user *buffer, size_t *lenp, loff_t *ppos);

#endif
@@ -703,7 +703,7 @@ static struct ctl_table kern_table[] = { 
		.data		= &dmesg_restrict,

		.maxlen		= sizeof(int),

		.mode		= 0644,

		.proc_handler	= proc_dointvec_minmax,

		.proc_handler	= proc_dointvec_minmax_sysadmin,

		.extra1		= &zero,

		.extra2		= &one,

	},
@@ -712,7 +712,7 @@ static struct ctl_table kern_table[] = { 
		.data		= &kptr_restrict,

		.maxlen		= sizeof(int),

		.mode		= 0644,

		.proc_handler	= proc_dmesg_restrict,

		.proc_handler	= proc_dointvec_minmax_sysadmin,

		.extra1		= &zero,

		.extra2		= &two,

	},
@@ -1943,7 +1943,7 @@ static int proc_taint(struct ctl_table *table, int write, 
}



#ifdef CONFIG_PRINTK

static int proc_dmesg_restrict(struct ctl_table *table, int write,

static int proc_dointvec_minmax_sysadmin(struct ctl_table *table, int write,

				void __user *buffer, size_t *lenp, loff_t *ppos)

{

	if (write && !capable(CAP_SYS_ADMIN))