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Commit 1873bb81 authored by Ahmed S. Darwish's avatar Ahmed S. Darwish Committed by Linus Torvalds
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RAMOOPS: Don't overflow over non-allocated regions 



The current code mis-calculates the ramoops header size, leading to an
overflow over the next record at best, or over a non-allocated region at
worst.  Fix that calculation.

Signed-off-by: default avatarAhmed S. Darwish <darwish.07@gmail.com>
Acked-by: default avatarMarco Stornelli <marco.stornelli@gmail.com>
Cc: stable@kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ffc96d62

drivers/char/ramoops.c

+7 −5
Original line number Diff line number Diff line
@@ -29,7 +29,6 @@ 
#include <linux/ramoops.h>



#define RAMOOPS_KERNMSG_HDR "===="

#define RAMOOPS_HEADER_SIZE   (5 + sizeof(struct timeval))



#define RECORD_SIZE 4096
@@ -65,8 +64,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper, 
			struct ramoops_context, dump);

	unsigned long s1_start, s2_start;

	unsigned long l1_cpy, l2_cpy;

	int res;

	char *buf;

	int res, hdr_size;

	char *buf, *buf_orig;

	struct timeval timestamp;



	/* Only dump oopses if dump_oops is set */
@@ -74,6 +73,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper, 
		return;



	buf = (char *)(cxt->virt_addr + (cxt->count * RECORD_SIZE));

	buf_orig = buf;



	memset(buf, '\0', RECORD_SIZE);

	res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);

	buf += res;
@@ -81,8 +82,9 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper, 
	res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);

	buf += res;



	l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE));

	l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE) - l2_cpy);

	hdr_size = buf - buf_orig;

	l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - hdr_size));

	l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - hdr_size) - l2_cpy);



	s2_start = l2 - l2_cpy;

	s1_start = l1 - l1_cpy;