From 4f729fd9aadcd6727f7c44ff0fce279031de6b85 Mon Sep 17 00:00:00 2001 From: Carmelo AMOROSO Date: Wed, 14 Apr 2010 07:24:46 +0200 Subject: ldso: Add config option for controlling LD_PRELOAD On hardened system it could be useful to disable the use of LD_PRELOAD environment variable for preloading shared objects before the system libraries. So this patch add a config option, LDSO_PRELOAD_ENV_SUPPORT, to control this behaviour. It is enabled by default. Signed-off-by: Carmelo Amoroso Signed-off-by: Bernhard Reutner-Fischer --- ldso/ldso/ldso.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'ldso/ldso/ldso.c') diff --git a/ldso/ldso/ldso.c b/ldso/ldso/ldso.c index 0fbc8f135..a8224e2c7 100644 --- a/ldso/ldso/ldso.c +++ b/ldso/ldso/ldso.c @@ -47,7 +47,9 @@ /* Global variables used within the shared library loader */ char *_dl_library_path = NULL; /* Where we look for libraries */ +#ifdef __LDSO_PRELOAD_ENV_SUPPORT__ char *_dl_preload = NULL; /* Things to be loaded before the libs */ +#endif char *_dl_ldsopath = NULL; /* Location of the shared lib loader */ int _dl_errno = 0; /* We can't use the real errno in ldso */ size_t _dl_pagesize = 0; /* Store the page size for use later */ @@ -348,7 +350,9 @@ void _dl_get_ready_to_run(struct elf_resolve *tpnt, DL_LOADADDR_TYPE load_addr, auxvt[AT_UID].a_un.a_val == auxvt[AT_EUID].a_un.a_val && auxvt[AT_GID].a_un.a_val == auxvt[AT_EGID].a_un.a_val)) { _dl_secure = 0; +#ifdef __LDSO_PRELOAD_ENV_SUPPORT__ _dl_preload = _dl_getenv("LD_PRELOAD", envp); +#endif _dl_library_path = _dl_getenv("LD_LIBRARY_PATH", envp); } else { static const char unsecure_envvars[] = @@ -365,7 +369,9 @@ void _dl_get_ready_to_run(struct elf_resolve *tpnt, DL_LOADADDR_TYPE load_addr, /* We could use rawmemchr but this need not be fast. */ nextp = _dl_strchr(nextp, '\0') + 1; } while (*nextp != '\0'); +#ifdef __LDSO_PRELOAD_ENV_SUPPORT__ _dl_preload = NULL; +#endif _dl_library_path = NULL; /* SUID binaries can be exploited if they do LAZY relocation. */ unlazy = RTLD_NOW; @@ -625,6 +631,7 @@ void _dl_get_ready_to_run(struct elf_resolve *tpnt, DL_LOADADDR_TYPE load_addr, _dl_map_cache(); +#ifdef __LDSO_PRELOAD_ENV_SUPPORT__ if (_dl_preload) { char c, *str, *str2; @@ -680,6 +687,7 @@ void _dl_get_ready_to_run(struct elf_resolve *tpnt, DL_LOADADDR_TYPE load_addr, str++; } } +#endif /* __LDSO_PRELOAD_ENV_SUPPORT__ */ #ifdef __LDSO_PRELOAD_FILE_SUPPORT__ do { -- cgit v1.2.3