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Merge tag 'meminit-v5.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

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Pull stack init fix from Kees Cook:
 "This is a small update to the stack auto-initialization self-test code
  to deal with the Clang initialization pattern.

  It's been in linux-next for a couple weeks; I had waited a bit
  wondering if anything more substantial was going to show up, but
  nothing has, so I'm sending this now before it gets too late"

* tag 'meminit-v5.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  lib/test_stackinit: Handle Clang auto-initialization pattern
This commit is contained in:
Linus Torvalds
2019-06-18 10:42:08 -07:00
parent 29f785ff76 8c30d32b1a
commit 915ed9320c
1 changed files with 15 additions and 6 deletions
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21
lib/test_stackinit.c
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@@ -12,7 +12,7 @@
/* Exfiltration buffer. */
#define MAX_VAR_SIZE 128
static char check_buf[MAX_VAR_SIZE];
static u8 check_buf[MAX_VAR_SIZE];
/* Character array to trigger stack protector in all functions. */
#define VAR_BUFFER 32
@@ -106,9 +106,18 @@ static noinline __init int test_ ## name (void) \
\
/* Fill clone type with zero for per-field init. */ \
memset(&zero, 0x00, sizeof(zero)); \
/* Clear entire check buffer for 0xFF overlap test. */ \
memset(check_buf, 0x00, sizeof(check_buf)); \
/* Fill stack with 0xFF. */ \
ignored = leaf_ ##name((unsigned long)&ignored, 1, \
FETCH_ARG_ ## which(zero)); \
/* Verify all bytes overwritten with 0xFF. */ \
for (sum = 0, i = 0; i < target_size; i++) \
sum += (check_buf[i] != 0xFF); \
if (sum) { \
pr_err(#name ": leaf fill was not 0xFF!?\n"); \
return 1; \
} \
/* Clear entire check buffer for later bit tests. */ \
memset(check_buf, 0x00, sizeof(check_buf)); \
/* Extract stack-defined variable contents. */ \
@@ -126,9 +135,9 @@ static noinline __init int test_ ## name (void) \
return 1; \
} \
\
/* Look for any set bits in the check region. */ \
for (i = 0; i < sizeof(check_buf); i++) \
sum += (check_buf[i] != 0); \
/* Look for any bytes still 0xFF in check region. */ \
for (sum = 0, i = 0; i < target_size; i++) \
sum += (check_buf[i] == 0xFF); \
\
if (sum == 0) \
pr_info(#name " ok\n"); \
@@ -162,13 +171,13 @@ static noinline __init int leaf_ ## name(unsigned long sp, \
* Keep this buffer around to make sure we've got a \
* stack frame of SOME kind... \
*/ \
memset(buf, (char)(sp && 0xff), sizeof(buf)); \
memset(buf, (char)(sp & 0xff), sizeof(buf)); \
/* Fill variable with 0xFF. */ \
if (fill) { \
fill_start = &var; \
fill_size = sizeof(var); \
memset(fill_start, \
(char)((sp && 0xff) | forced_mask), \
(char)((sp & 0xff) | forced_mask), \
fill_size); \
} \
\