| From | Andi Kleen <> | Subject | [PATCH] [115/139] RAMOOPS: Don't overflow over non-allocated regions | Date | Tue, 1 Feb 2011 16:45:14 -0800 (PST) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Ahmed S. Darwish <darwish.07@gmail.com>
commit 1873bb8115e678ad9fd0aac9dbbc68383bc36e06 upstream.
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> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Andi Kleen <ak@linux.intel.com>
--- drivers/char/ramoops.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
Index: linux-2.6.35.y/drivers/char/ramoops.c =================================================================== --- linux-2.6.35.y.orig/drivers/char/ramoops.c +++ linux-2.6.35.y/drivers/char/ramoops.c @@ -27,7 +27,6 @@ #include <linux/ioport.h> #define RAMOOPS_KERNMSG_HDR "====" -#define RAMOOPS_HEADER_SIZE (5 + sizeof(struct timeval)) #define RECORD_SIZE 4096 @@ -63,8 +62,8 @@ static void ramoops_do_dump(struct kmsg_ 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 */ @@ -72,6 +71,8 @@ static void ramoops_do_dump(struct kmsg_ 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; @@ -79,8 +80,9 @@ static void ramoops_do_dump(struct kmsg_ 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;
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