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authorAhmed S. Darwish <darwish.07@gmail.com>2010-12-25 04:57:09 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2010-12-28 14:12:32 -0500
commit1873bb8115e678ad9fd0aac9dbbc68383bc36e06 (patch)
tree938017e949de036589035da33975257e68afed65 /drivers/char/ramoops.c
parentffc96d628b651b69b39909fc3e9e8f465df1eed3 (diff)
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: Ahmed S. Darwish <darwish.07@gmail.com> Acked-by: Marco Stornelli <marco.stornelli@gmail.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/char/ramoops.c')
-rw-r--r--drivers/char/ramoops.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/char/ramoops.c b/drivers/char/ramoops.c
index 73dcb0ee41fd..d3d63be2cd37 100644
--- a/drivers/char/ramoops.c
+++ b/drivers/char/ramoops.c
@@ -29,7 +29,6 @@
29#include <linux/ramoops.h> 29#include <linux/ramoops.h>
30 30
31#define RAMOOPS_KERNMSG_HDR "====" 31#define RAMOOPS_KERNMSG_HDR "===="
32#define RAMOOPS_HEADER_SIZE (5 + sizeof(struct timeval))
33 32
34#define RECORD_SIZE 4096 33#define RECORD_SIZE 4096
35 34
@@ -65,8 +64,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper,
65 struct ramoops_context, dump); 64 struct ramoops_context, dump);
66 unsigned long s1_start, s2_start; 65 unsigned long s1_start, s2_start;
67 unsigned long l1_cpy, l2_cpy; 66 unsigned long l1_cpy, l2_cpy;
68 int res; 67 int res, hdr_size;
69 char *buf; 68 char *buf, *buf_orig;
70 struct timeval timestamp; 69 struct timeval timestamp;
71 70
72 /* Only dump oopses if dump_oops is set */ 71 /* Only dump oopses if dump_oops is set */
@@ -74,6 +73,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper,
74 return; 73 return;
75 74
76 buf = (char *)(cxt->virt_addr + (cxt->count * RECORD_SIZE)); 75 buf = (char *)(cxt->virt_addr + (cxt->count * RECORD_SIZE));
76 buf_orig = buf;
77
77 memset(buf, '\0', RECORD_SIZE); 78 memset(buf, '\0', RECORD_SIZE);
78 res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR); 79 res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
79 buf += res; 80 buf += res;
@@ -81,8 +82,9 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper,
81 res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec); 82 res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
82 buf += res; 83 buf += res;
83 84
84 l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE)); 85 hdr_size = buf - buf_orig;
85 l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE) - l2_cpy); 86 l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - hdr_size));
87 l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - hdr_size) - l2_cpy);
86 88
87 s2_start = l2 - l2_cpy; 89 s2_start = l2 - l2_cpy;
88 s1_start = l1 - l1_cpy; 90 s1_start = l1 - l1_cpy;