From f94446c38fb3f4ad26183984c490a9590cd05282 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Wed, 6 Dec 2023 10:24:02 -0300 Subject: elf: Do not set invalid tunables values The loader now warns for invalid and out-of-range tunable values. The patch also fixes the parsing of size_t maximum values, where _dl_strtoul was failing for large values close to SIZE_MAX. Checked on x86_64-linux-gnu. Reviewed-by: Siddhesh Poyarekar --- elf/dl-misc.c | 9 ++++++++- elf/dl-tunables.c | 35 ++++++++++++++++++++++++++++++----- elf/tst-tunables.c | 30 ++++++++++++++++++++++++++++++ 3 files changed, 68 insertions(+), 6 deletions(-) (limited to 'elf') diff --git a/elf/dl-misc.c b/elf/dl-misc.c index 5b84adc2f4..859d3e26f0 100644 --- a/elf/dl-misc.c +++ b/elf/dl-misc.c @@ -174,6 +174,9 @@ _dl_strtoul (const char *nptr, char **endptr) return 0UL; } + uint64_t cutoff = (UINT64_MAX * 2UL + 1UL) / 10; + uint64_t cutlim = (UINT64_MAX * 2UL + 1UL) % 10; + int base = 10; max_digit = 9; if (*nptr == '0') @@ -182,11 +185,15 @@ _dl_strtoul (const char *nptr, char **endptr) { base = 16; nptr += 2; + cutoff = (UINT64_MAX * 2UL + 1UL) / 16; + cutlim = (UINT64_MAX * 2UL + 1UL) % 16; } else { base = 8; max_digit = 7; + cutoff = (UINT64_MAX * 2UL + 1UL) / 8; + cutlim = (UINT64_MAX * 2UL + 1UL) % 8; } } @@ -207,7 +214,7 @@ _dl_strtoul (const char *nptr, char **endptr) else break; - if (result >= (UINT64_MAX - digval) / base) + if (result > cutoff || (result == cutoff && digval > cutlim)) { if (endptr != NULL) *endptr = (char *) nptr; diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c index 3d41e8e28e..092b696484 100644 --- a/elf/dl-tunables.c +++ b/elf/dl-tunables.c @@ -69,16 +69,27 @@ do_tunable_update_val (tunable_t *cur, const tunable_val_t *valp, { tunable_num_t val, min, max; - if (cur->type.type_code == TUNABLE_TYPE_STRING) + switch (cur->type.type_code) { + case TUNABLE_TYPE_STRING: cur->val.strval = valp->strval; cur->initialized = true; return; + case TUNABLE_TYPE_INT_32: + val = (int32_t) valp->numval; + break; + case TUNABLE_TYPE_UINT_64: + val = (int64_t) valp->numval; + break; + case TUNABLE_TYPE_SIZE_T: + val = (size_t) valp->numval; + break; + default: + __builtin_unreachable (); } bool unsigned_cmp = unsigned_tunable_type (cur->type.type_code); - val = valp->numval; min = minp != NULL ? *minp : cur->type.min; max = maxp != NULL ? *maxp : cur->type.max; @@ -109,16 +120,24 @@ do_tunable_update_val (tunable_t *cur, const tunable_val_t *valp, /* Validate range of the input value and initialize the tunable CUR if it looks good. */ -static void +static bool tunable_initialize (tunable_t *cur, const char *strval, size_t len) { tunable_val_t val = { 0 }; if (cur->type.type_code != TUNABLE_TYPE_STRING) - val.numval = (tunable_num_t) _dl_strtoul (strval, NULL); + { + char *endptr = NULL; + uint64_t numval = _dl_strtoul (strval, &endptr); + if (endptr != strval + len) + return false; + val.numval = (tunable_num_t) numval; + } else val.strval = (struct tunable_str_t) { strval, len }; do_tunable_update_val (cur, &val, NULL, NULL); + + return true; } bool @@ -225,7 +244,13 @@ parse_tunables (const char *valstring) } for (int i = 0; i < ntunables; i++) - tunable_initialize (tunables[i].t, tunables[i].value, tunables[i].len); + if (!tunable_initialize (tunables[i].t, tunables[i].value, + tunables[i].len)) + _dl_error_printf ("WARNING: ld.so: invalid GLIBC_TUNABLES value `%.*s' " + "for option `%s': ignored.\n", + (int) tunables[i].len, + tunables[i].value, + tunables[i].t->name); } /* Initialize the tunables list from the environment. For now we only use the diff --git a/elf/tst-tunables.c b/elf/tst-tunables.c index 188345b070..d6a1e1b3ac 100644 --- a/elf/tst-tunables.c +++ b/elf/tst-tunables.c @@ -53,6 +53,13 @@ static const struct test_t 4096, 0, }, + { + "GLIBC_TUNABLES", + "glibc.malloc.mmap_threshold=-1", + 0, + SIZE_MAX, + 0, + }, /* Empty tunable are ignored. */ { "GLIBC_TUNABLES", @@ -224,6 +231,29 @@ static const struct test_t 0, 0, }, + /* Invalid numbers are ignored. */ + { + "GLIBC_TUNABLES", + "glibc.malloc.check=abc:glibc.malloc.mmap_threshold=4096", + 0, + 4096, + 0, + }, + { + "GLIBC_TUNABLES", + "glibc.malloc.check=2:glibc.malloc.mmap_threshold=abc", + 2, + 0, + 0, + }, + { + "GLIBC_TUNABLES", + /* SIZE_MAX + 1 */ + "glibc.malloc.mmap_threshold=18446744073709551616", + 0, + 0, + 0, + }, /* Also check some tunable aliases. */ { "MALLOC_CHECK_", -- cgit 1.4.1