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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
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>
authored by Ahmed S. Darwish and committed by Linus Torvalds 1873bb81 ffc96d62
+7
-5
drivers/char/ramoops.c
+7
-5
drivers/char/ramoops.c
···
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#include <linux/ramoops.h>
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#define RAMOOPS_KERNMSG_HDR "===="
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-
#define RAMOOPS_HEADER_SIZE (5 + sizeof(struct timeval))
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#define RECORD_SIZE 4096
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···
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struct ramoops_context, dump);
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unsigned long s1_start, s2_start;
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unsigned long l1_cpy, l2_cpy;
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-
int res;
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-
char *buf;
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+
int res, hdr_size;
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+
char *buf, *buf_orig;
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struct timeval timestamp;
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/* Only dump oopses if dump_oops is set */
···
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return;
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buf = (char *)(cxt->virt_addr + (cxt->count * RECORD_SIZE));
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+
buf_orig = buf;
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+
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memset(buf, '\0', RECORD_SIZE);
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res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
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buf += res;
···
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res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
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buf += res;
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-
l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE));
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-
l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE) - l2_cpy);
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+
hdr_size = buf - buf_orig;
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+
l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - hdr_size));
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+
l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - hdr_size) - l2_cpy);
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s2_start = l2 - l2_cpy;
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s1_start = l1 - l1_cpy;