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authorDamjan Marion <damarion@cisco.com>2022-03-26 00:57:50 +0100
committerBeno�t Ganne <bganne@cisco.com>2022-03-28 10:04:31 +0000
commit87997686ee9a6c7aecec423f05bec21a938ec9bb (patch)
tree9772c2abf6befda27715951e852d88eb5380f564 /src/vppinfra/hash.c
parenta5bfe6cd0e0b1e413bbb2decfcdb97c65b79cbce (diff)
vppinfra: avoid mem overflow in hash_memory()
Change-Id: Ic81aafd5f378de06e5ea8cdd6a59e07ff1a7afca Type: improvement Signed-off-by: Damjan Marion <damarion@cisco.com>
Diffstat (limited to 'src/vppinfra/hash.c')
-rw-r--r--src/vppinfra/hash.c230
1 files changed, 21 insertions, 209 deletions
diff --git a/src/vppinfra/hash.c b/src/vppinfra/hash.c
index 7b8869254e1..7c1dcd4c57b 100644
--- a/src/vppinfra/hash.c
+++ b/src/vppinfra/hash.c
@@ -77,241 +77,53 @@ set_is_user (void *v, uword i, uword is_user)
static u8 *hash_format_pair_default (u8 * s, va_list * args);
-#if uword_bits == 64
-
-static inline u64
-zap64 (u64 x, word n)
-{
-#define _(n) (((u64) 1 << (u64) (8*(n))) - (u64) 1)
- static u64 masks_little_endian[] = {
- 0, _(1), _(2), _(3), _(4), _(5), _(6), _(7),
- };
- static u64 masks_big_endian[] = {
- 0, ~_(7), ~_(6), ~_(5), ~_(4), ~_(3), ~_(2), ~_(1),
- };
-#undef _
- if (clib_arch_is_big_endian)
- return x & masks_big_endian[n];
- else
- return x & masks_little_endian[n];
-}
-
-/**
- * make address-sanitizer skip this:
- * clib_mem_unaligned + zap64 casts its input as u64, computes a mask
- * according to the input length, and returns the casted maked value.
- * Therefore all the 8 Bytes of the u64 are systematically read, which
- * rightfully causes address-sanitizer to raise an error on smaller inputs.
- *
- * However the invalid Bytes are discarded within zap64(), which is why
- * this can be silenced safely.
- *
- * The above is true *unless* the extra bytes cross a page boundary
- * into unmapped or no-access space, hence the boundary crossing check.
- */
-static inline u64
-hash_memory64 (void *p, word n_bytes, u64 state)
+__clib_export uword
+hash_memory (void *p, word n_bytes, uword state)
{
- u64 *q = p;
+ uword last[3] = {};
+ uwordu *q = p;
u64 a, b, c, n;
- int page_boundary_crossing;
- u64 start_addr, end_addr;
- union
- {
- u8 as_u8[8];
- u64 as_u64;
- } tmp;
-
- /*
- * If the request crosses a 4k boundary, it's not OK to assume
- * that the zap64 game is safe. 4k is the minimum known page size.
- */
- start_addr = (u64) p;
- end_addr = start_addr + n_bytes + 7;
- page_boundary_crossing = (start_addr >> 12) != (end_addr >> 12);
-
- a = b = 0x9e3779b97f4a7c13LL;
- c = state;
- n = n_bytes;
-
- while (n >= 3 * sizeof (u64))
- {
- a += clib_mem_unaligned (q + 0, u64);
- b += clib_mem_unaligned (q + 1, u64);
- c += clib_mem_unaligned (q + 2, u64);
- hash_mix64 (a, b, c);
- n -= 3 * sizeof (u64);
- q += 3;
- }
-
- c += n_bytes;
- switch (n / sizeof (u64))
- {
- case 2:
- a += clib_mem_unaligned (q + 0, u64);
- b += clib_mem_unaligned (q + 1, u64);
- if (n % sizeof (u64))
- {
- if (PREDICT_TRUE (page_boundary_crossing == 0))
- {
- CLIB_MEM_OVERFLOW_PUSH (q + 2, sizeof (u64));
- c += zap64 (clib_mem_unaligned (q + 2, u64), n % sizeof (u64))
- << 8;
- CLIB_MEM_OVERFLOW_POP ();
- }
- else
- {
- clib_memcpy_fast (tmp.as_u8, q + 2, n % sizeof (u64));
- c += zap64 (tmp.as_u64, n % sizeof (u64)) << 8;
- }
- }
- break;
-
- case 1:
- a += clib_mem_unaligned (q + 0, u64);
- if (n % sizeof (u64))
- {
- if (PREDICT_TRUE (page_boundary_crossing == 0))
- {
- CLIB_MEM_OVERFLOW_PUSH (q + 1, sizeof (u64));
- b += zap64 (clib_mem_unaligned (q + 1, u64), n % sizeof (u64));
- CLIB_MEM_OVERFLOW_POP ();
- }
- else
- {
- clib_memcpy_fast (tmp.as_u8, q + 1, n % sizeof (u64));
- b += zap64 (tmp.as_u64, n % sizeof (u64));
- }
- }
- break;
-
- case 0:
- if (n % sizeof (u64))
- {
- if (PREDICT_TRUE (page_boundary_crossing == 0))
- {
- CLIB_MEM_OVERFLOW_PUSH (q + 0, sizeof (u64));
- a += zap64 (clib_mem_unaligned (q + 0, u64), n % sizeof (u64));
- CLIB_MEM_OVERFLOW_POP ();
- }
- else
- {
- clib_memcpy_fast (tmp.as_u8, q, n % sizeof (u64));
- a += zap64 (tmp.as_u64, n % sizeof (u64));
- }
- }
- break;
- }
-
- hash_mix64 (a, b, c);
- return c;
-}
-
-#else /* if uword_bits == 64 */
-
-static inline u32
-zap32 (u32 x, word n)
-{
-#define _(n) (((u32) 1 << (u32) (8*(n))) - (u32) 1)
- static u32 masks_little_endian[] = {
- 0, _(1), _(2), _(3),
- };
- static u32 masks_big_endian[] = {
- 0, ~_(3), ~_(2), ~_(1),
- };
-#undef _
- if (clib_arch_is_big_endian)
- return x & masks_big_endian[n];
- else
- return x & masks_little_endian[n];
-}
-
-static inline u32
-hash_memory32 (void *p, word n_bytes, u32 state)
-{
- u32 *q = p;
- u32 a, b, c, n;
-
- a = b = 0x9e3779b9;
+ a = b = (uword_bits == 64) ? 0x9e3779b97f4a7c13LL : 0x9e3779b9;
c = state;
n = n_bytes;
- while (n >= 3 * sizeof (u32))
+ while (n >= 3 * sizeof (uword))
{
- a += clib_mem_unaligned (q + 0, u32);
- b += clib_mem_unaligned (q + 1, u32);
- c += clib_mem_unaligned (q + 2, u32);
- hash_mix32 (a, b, c);
- n -= 3 * sizeof (u32);
+ a += q[0];
+ b += q[1];
+ c += q[2];
+ hash_mix (a, b, c);
+ n -= 3 * sizeof (uword);
q += 3;
}
c += n_bytes;
- switch (n / sizeof (u32))
- {
- case 2:
- a += clib_mem_unaligned (q + 0, u32);
- b += clib_mem_unaligned (q + 1, u32);
- if (n % sizeof (u32))
- c += zap32 (clib_mem_unaligned (q + 2, u32), n % sizeof (u32)) << 8;
- break;
- case 1:
- a += clib_mem_unaligned (q + 0, u32);
- if (n % sizeof (u32))
- b += zap32 (clib_mem_unaligned (q + 1, u32), n % sizeof (u32));
- break;
-
- case 0:
- if (n % sizeof (u32))
- a += zap32 (clib_mem_unaligned (q + 0, u32), n % sizeof (u32));
- break;
+ if (n > 0)
+ {
+ clib_memcpy_fast (&last, q, n);
+ a += last[0];
+ b += last[1];
+ c += last[2];
}
- hash_mix32 (a, b, c);
+ hash_mix (a, b, c);
return c;
}
-#endif
-
-__clib_export uword
-hash_memory (void *p, word n_bytes, uword state)
-{
- uword *q = p;
-
-#if uword_bits == 64
- return hash_memory64 (q, n_bytes, state);
-#else
- return hash_memory32 (q, n_bytes, state);
-#endif
-}
-
-#if uword_bits == 64
-always_inline uword
-hash_uword (uword x)
-{
- u64 a, b, c;
- a = b = 0x9e3779b97f4a7c13LL;
- c = 0;
- a += x;
- hash_mix64 (a, b, c);
- return c;
-}
-#else
always_inline uword
hash_uword (uword x)
{
- u32 a, b, c;
+ uword a, b, c;
- a = b = 0x9e3779b9;
+ a = b = (uword_bits == 64) ? 0x9e3779b97f4a7c13LL : 0x9e3779b9;
c = 0;
a += x;
- hash_mix32 (a, b, c);
+ hash_mix (a, b, c);
return c;
}
-#endif
/* Call sum function. Hash code will be sum function value
modulo the prime length of the hash table. */