From: Matthew Garrett
Git-commit: Not yet, reviewing
Patch-mainline: Not yet, reviewing
References: fate#314486
Target: SLE-11 SP3
Allowing users to write to address space makes it possible for the kernel
to be subverted. Restrict this when we need to protect the kernel.
Signed-off-by: Matthew Garrett
Acked-by: Lee, Chun-Yi
---
drivers/char/mem.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -159,6 +159,9 @@ static ssize_t write_mem(struct file *fi
unsigned long copied;
void *ptr;
+ if (!capable(CAP_COMPROMISE_KERNEL))
+ return -EPERM;
+
if (!valid_phys_addr_range(p, count))
return -EFAULT;
@@ -542,6 +545,9 @@ static ssize_t write_kmem(struct file *f
char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
int err = 0;
+ if (!capable(CAP_COMPROMISE_KERNEL))
+ return -EPERM;
+
if (p < (unsigned long) high_memory) {
unsigned long to_write = min_t(unsigned long, count,
(unsigned long)high_memory - p);
--
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