*************************************************/
/* Copyright (c) University of Cambridge 1995 - 2018 */
-/* Copyright (c) The Exim maintainers 2019 */
+/* Copyright (c) The Exim maintainers 2019 - 2020 */
/* See the file NOTICE for conditions of use and distribution. */
/* Exim gets and frees all its store through these functions. In the original
This means it can be freed when search_tidyup() is called to close down all
the lookup caching.
+- There is another pool (POOL_MESSAGE) used for medium-lifetime objects; within
+ a single message transaction but needed for longer than the use of the main
+ pool permits. Currently this means only receive-time DKIM information.
+
. Orthogonal to the three pool types, there are two classes of memory: untainted
and tainted. The latter is used for values derived from untrusted input, and
the string-expansion mechanism refuses to operate on such values (obviously,
it can expand an untainted value to return a tainted result). The classes
- are implemented by duplicating the three pool types. Pool resets are requested
+ are implemented by duplicating the four pool types. Pool resets are requested
against the nontainted sibling and apply to both siblings.
Only memory blocks requested for tainted use are regarded as tainted; anything
to not copy untrusted data into untainted memory, as downstream taint-checks
would be avoided.
- Internally we currently use malloc for nontainted pools, and mmap for tainted
- pools. The disparity is for speed of testing the taintedness of pointers;
- because Linux appears to use distinct non-overlapping address allocations for
- mmap vs. everything else, which means only two pointer-compares suffice for the
- test. Other OS' cannot use that optimisation, and a more lengthy test against
- the limits of tainted-pool allcations has to be done.
-
Intermediate layers (eg. the string functions) can test for taint, and use this
for ensurinng that results have proper state. For example the
string_vformat_trc() routing supporting the string_sprintf() interface will
int store_pool = POOL_MAIN;
-#define NPOOLS 6
static storeblock *chainbase[NPOOLS];
static storeblock *current_block[NPOOLS];
static void *next_yield[NPOOLS];
-static int yield_length[NPOOLS] = { -1, -1, -1, -1, -1, -1 };
-
-/* The limits of the tainted pools. Tracking these on new allocations enables
-a fast is_tainted implementation. We assume the kernel only allocates mmaps using
-one side or the other of data+heap, not both. */
-
-void * tainted_base = (void *)-1;
-void * tainted_top = (void *)0;
+static int yield_length[NPOOLS];
/* pool_malloc holds the amount of memory used by the store pools; this goes up
and down as store is reset or released. nonpool_malloc is the total got by
[POOL_MAIN] = US"main",
[POOL_PERM] = US"perm",
[POOL_SEARCH] = US"search",
+[POOL_MESSAGE] = US"message",
[POOL_TAINT_MAIN] = US"main",
[POOL_TAINT_PERM] = US"perm",
[POOL_TAINT_SEARCH] = US"search",
+[POOL_TAINT_SEARCH] = US"search",
+[POOL_TAINT_MESSAGE] = US"message",
};
static const uschar * poolclass[NPOOLS] = {
[POOL_MAIN] = US"untainted",
[POOL_PERM] = US"untainted",
[POOL_SEARCH] = US"untainted",
+[POOL_MESSAGE] = US"untainted",
[POOL_TAINT_MAIN] = US"tainted",
[POOL_TAINT_PERM] = US"tainted",
[POOL_TAINT_SEARCH] = US"tainted",
+[POOL_TAINT_MESSAGE] = US"tainted",
};
#endif
-static void * store_mmap(int, const char *, int);
static void * internal_store_malloc(int, const char *, int);
-static void internal_untainted_free(void *, const char *, int linenumber);
-static void internal_tainted_free(storeblock *, const char *, int linenumber);
+static void internal_store_free(void *, const char *, int linenumber);
+
+/******************************************************************************/
+/* Initialisation, for things fragile with parameter channges when using
+static initialisers. */
+
+void
+store_init(void)
+{
+for (int i = 0; i < NPOOLS; i++) yield_length[i] = -1;
+}
/******************************************************************************/
if ((b = current_block[pool]))
{
uschar * bc = US b + ALIGNED_SIZEOF_STOREBLOCK;
- if (US p >= bc && US p <= bc + b->length) return TRUE;
+ if (US p >= bc && US p < bc + b->length) return TRUE;
}
for (int pool = POOL_TAINT_BASE; pool < nelem(chainbase); pool++)
for (b = chainbase[pool]; b; b = b->next)
{
uschar * bc = US b + ALIGNED_SIZEOF_STOREBLOCK;
- if (US p >= bc && US p <= bc + b->length) return TRUE;
+ if (US p >= bc && US p < bc + b->length) return TRUE;
}
return FALSE;
}
msg, func, line);
}
-static void
-use_slow_taint_check(const uschar * why)
-{
-#ifndef COMPILE_UTILITY
-DEBUG(D_any)
- debug_printf("switching to slow-mode taint checking (after %s) "
- "taint bounds %p %p\n", why, tainted_base, tainted_top);
-#endif
-f.taint_check_slow = TRUE;
-}
-
-/* If the creation of a new tainted region results in any of the
-untainted regions appearing to be tainted, using the fast-mode test,
-we need to switch to safe-but-slow mode. */
-
-static void
-verify_all_untainted(void)
-{
-for (int pool = 0; pool < POOL_TAINT_BASE; pool++)
- for (storeblock * b = chainbase[pool]; b; b = b->next)
- {
- uschar * bc = US b + ALIGNED_SIZEOF_STOREBLOCK;
- if (is_tainted(bc))
- {
- use_slow_taint_check(US"mmap");
- return;
- }
- }
-}
-
/*************************************************
{
/* Give up on this block, because it's too small */
nblocks[pool]--;
- if (pool < POOL_TAINT_BASE)
- internal_untainted_free(newblock, func, linenumber);
- else
- internal_tainted_free(newblock, func, linenumber);
+ internal_store_free(newblock, func, linenumber);
newblock = NULL;
}
if (++nblocks[pool] > maxblocks[pool])
maxblocks[pool] = nblocks[pool];
- newblock = tainted
- ? store_mmap(mlength, func, linenumber)
- : internal_store_malloc(mlength, func, linenumber);
+ newblock = internal_store_malloc(mlength, func, linenumber);
newblock->next = NULL;
newblock->length = length;
/* Cut out the debugging stuff for utilities, but stop picky compilers from
giving warnings. */
-#ifdef COMPILE_UTILITY
-func = func;
-linenumber = linenumber;
-#else
+#ifndef COMPILE_UTILITY
DEBUG(D_memory)
debug_printf("---%d Get %6p %5d %-14s %4d\n", pool,
store_last_get[pool], size, func, linenumber);
/* Cut out the debugging stuff for utilities, but stop picky compilers from
giving warnings. */
-#ifdef COMPILE_UTILITY
-func = func;
-linenumber = linenumber;
-#else
+#ifndef COMPILE_UTILITY
DEBUG(D_memory)
debug_printf("---%d Ext %6p %5d %-14s %4d\n", pool, ptr, newsize,
func, linenumber);
nbytes[pool] -= siz;
pool_malloc -= siz;
nblocks[pool]--;
- if (pool < POOL_TAINT_BASE)
- internal_untainted_free(b, func, linenumber);
- else
- internal_tainted_free(b, func, linenumber);
+ internal_store_free(b, func, linenumber);
}
/* Cut out the debugging stuff for utilities, but stop picky compilers from
giving warnings. */
-#ifdef COMPILE_UTILITY
-func = func;
-linenumber = linenumber;
-#else
+#ifndef COMPILE_UTILITY
DEBUG(D_memory)
debug_printf("---%d Rst %6p %5d %-14s %4d %d\n", pool, ptr,
count + oldmalloc - pool_malloc,
rmark
-store_reset_3(rmark r, int pool, const char *func, int linenumber)
+store_reset_3(rmark r, const char *func, int linenumber)
{
void ** ptr = r;
-if (pool >= POOL_TAINT_BASE)
+if (store_pool >= POOL_TAINT_BASE)
log_write(0, LOG_MAIN|LOG_PANIC_DIE,
- "store_reset called for pool %d: %s %d\n", pool, func, linenumber);
+ "store_reset called for pool %d: %s %d\n", store_pool, func, linenumber);
if (!r)
log_write(0, LOG_MAIN|LOG_PANIC_DIE,
"store_reset called with bad mark: %s %d\n", func, linenumber);
-internal_store_reset(*ptr, pool + POOL_TAINT_BASE, func, linenumber);
-internal_store_reset(ptr, pool, func, linenumber);
+internal_store_reset(*ptr, store_pool + POOL_TAINT_BASE, func, linenumber);
+internal_store_reset(ptr, store_pool, func, linenumber);
return NULL;
}
/* Cut out the debugging stuff for utilities, but stop picky compilers from
giving warnings. */
-#ifdef COMPILE_UTILITY
- func = func;
- linenumber = linenumber;
-#else
+#ifndef COMPILE_UTILITY
DEBUG(D_memory)
debug_printf("---%d Rel %6p %5d %-14s %4d %d\n", pool, ptr, count,
func, linenumber, pool_malloc);
/* Cut out the debugging stuff for utilities, but stop picky compilers
from giving warnings. */
-#ifdef COMPILE_UTILITY
- func = func;
- linenumber = linenumber;
-#else
+#ifndef COMPILE_UTILITY
DEBUG(D_memory)
debug_printf("-Release %6p %-20s %4d %d\n", (void *)bb, func,
linenumber, pool_malloc);
-/******************************************************************************/
-static void *
-store_alloc_tail(void * yield, int size, const char * func, int line,
- const uschar * type)
-{
-if ((nonpool_malloc += size) > max_nonpool_malloc)
- max_nonpool_malloc = nonpool_malloc;
-
-/* Cut out the debugging stuff for utilities, but stop picky compilers from
-giving warnings. */
-
-#ifdef COMPILE_UTILITY
-func = func; line = line; type = type;
-#else
-
-/* If running in test harness, spend time making sure all the new store
-is not filled with zeros so as to catch problems. */
-
-if (f.running_in_test_harness)
- memset(yield, 0xF0, (size_t)size);
-DEBUG(D_memory) debug_printf("--%6s %6p %5d bytes\t%-14s %4d\tpool %5d nonpool %5d\n",
- type, yield, size, func, line, pool_malloc, nonpool_malloc);
-#endif /* COMPILE_UTILITY */
-
-return yield;
-}
-
-/*************************************************
-* Mmap store *
-*************************************************/
-
-static void *
-store_mmap(int size, const char * func, int line)
-{
-void * yield, * top;
-
-if (size < 16) size = 16;
-
-if (!(yield = mmap(NULL, (size_t)size,
- PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)))
- log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to mmap %d bytes of memory: "
- "called from line %d of %s", size, line, func);
-
-if (yield < tainted_base) tainted_base = yield;
-if ((top = US yield + size) > tainted_top) tainted_top = top;
-if (!f.taint_check_slow) verify_all_untainted();
-
-return store_alloc_tail(yield, size, func, line, US"Mmap");
-}
-
/*************************************************
* Malloc store *
*************************************************/
Arguments:
size amount of store wanted
func function from which called
- linenumber line number in source file
+ line line number in source file
Returns: pointer to gotten store (panic on failure)
*/
static void *
-internal_store_malloc(int size, const char *func, int linenumber)
+internal_store_malloc(int size, const char *func, int line)
{
void * yield;
if (!(yield = malloc((size_t)size)))
log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to malloc %d bytes of memory: "
- "called from line %d in %s", size, linenumber, func);
+ "called from line %d in %s", size, line, func);
+
+if ((nonpool_malloc += size) > max_nonpool_malloc)
+ max_nonpool_malloc = nonpool_malloc;
-/* If malloc ever returns apparently tainted memory, which glibc
-malloc will as it uses mmap for larger requests, we must switch to
-the slower checking for tainting (checking an address against all
-the tainted pool block spans, rather than just the mmap span) */
+/* Cut out the debugging stuff for utilities, but stop picky compilers from
+giving warnings. */
-if (!f.taint_check_slow && is_tainted(yield))
- use_slow_taint_check(US"malloc");
+#ifndef COMPILE_UTILITY
+/* If running in test harness, spend time making sure all the new store
+is not filled with zeros so as to catch problems. */
-return store_alloc_tail(yield, size, func, linenumber, US"Malloc");
+if (f.running_in_test_harness)
+ memset(yield, 0xF0, (size_t)size);
+DEBUG(D_memory) debug_printf("--Malloc %6p %5d bytes\t%-14s %4d\tpool %5d nonpool %5d\n",
+ yield, size, func, line, pool_malloc, nonpool_malloc);
+#endif /* COMPILE_UTILITY */
+
+return yield;
}
void *
*/
static void
-internal_untainted_free(void * block, const char * func, int linenumber)
+internal_store_free(void * block, const char * func, int linenumber)
{
-#ifdef COMPILE_UTILITY
-func = func;
-linenumber = linenumber;
-#else
+#ifndef COMPILE_UTILITY
DEBUG(D_memory)
debug_printf("----Free %6p %-20s %4d\n", block, func, linenumber);
#endif /* COMPILE_UTILITY */
store_free_3(void * block, const char * func, int linenumber)
{
n_nonpool_blocks--;
-internal_untainted_free(block, func, linenumber);
-}
-
-/******************************************************************************/
-static void
-internal_tainted_free(storeblock * block, const char * func, int linenumber)
-{
-#ifdef COMPILE_UTILITY
-func = func;
-linenumber = linenumber;
-#else
-DEBUG(D_memory)
- debug_printf("---Unmap %6p %-20s %4d\n", block, func, linenumber);
-#endif
-munmap((void *)block, block->length + ALIGNED_SIZEOF_STOREBLOCK);
+internal_store_free(block, func, linenumber);
}
/******************************************************************************/
#endif
}
+
+/******************************************************************************/
+/* Per-message pool management */
+
+static rmark message_reset_point = NULL;
+
+void
+message_start(void)
+{
+int oldpool = store_pool;
+store_pool = POOL_MESSAGE;
+if (!message_reset_point) message_reset_point = store_mark();
+store_pool = oldpool;
+}
+
+void message_tidyup(void)
+{
+int oldpool;
+if (!message_reset_point) return;
+oldpool = store_pool;
+store_pool = POOL_MESSAGE;
+message_reset_point = store_reset(message_reset_point);
+store_pool = oldpool;
+}
+
/* End of store.c */
git://git.exim.org / exim.git / blobdiff