diff options
| -rw-r--r-- | linker/linker.c | 56 |
1 files changed, 52 insertions, 4 deletions
diff --git a/linker/linker.c b/linker/linker.c index e398f82..77f995e 100644 --- a/linker/linker.c +++ b/linker/linker.c @@ -53,6 +53,10 @@ #define SO_MAX 96 +/* Assume average path length of 64 and max 8 paths */ +#define LDPATH_BUFSIZE 512 +#define LDPATH_MAX 8 + /* >>> IMPORTANT NOTE - READ ME BEFORE MODIFYING <<< * * Do NOT use malloc() and friends or pthread_*() code here. @@ -66,7 +70,6 @@ * - should we do anything special for STB_WEAK symbols? * - are we doing everything we should for ARM_COPY relocations? * - cleaner error reporting - * - configuration for paths (LD_LIBRARY_PATH?) * - after linking, set as much stuff as possible to READONLY * and NOEXEC * - linker hardcodes PAGE_SIZE and PAGE_MASK because the kernel @@ -89,6 +92,9 @@ static soinfo *freelist = NULL; static soinfo *solist = &libdl_info; static soinfo *sonext = &libdl_info; +static char ldpaths_buf[LDPATH_BUFSIZE]; +static const char *ldpaths[LDPATH_MAX + 1]; + int debug_verbosity; static int pid; @@ -503,13 +509,12 @@ static int _open_lib(const char *name) return -1; } -/* TODO: Need to add support for initializing the so search path with - * LD_LIBRARY_PATH env variable for non-setuid programs. */ static int open_library(const char *name) { int fd; char buf[512]; const char **path; + int n; TRACE("[ %5d opening %s ]\n", pid, name); @@ -519,8 +524,21 @@ static int open_library(const char *name) if ((name[0] == '/') && ((fd = _open_lib(name)) >= 0)) return fd; + for (path = ldpaths; *path; path++) { + n = snprintf(buf, sizeof(buf), "%s/%s", *path, name); + if (n < 0 || n >= (int)sizeof(buf)) { + WARN("Ignoring very long library path: %s/%s\n", *path, name); + continue; + } + if ((fd = _open_lib(buf)) >= 0) + return fd; + } for (path = sopaths; *path; path++) { - snprintf(buf, sizeof(buf), "%s/%s", *path, name); + n = snprintf(buf, sizeof(buf), "%s/%s", *path, name); + if (n < 0 || n >= (int)sizeof(buf)) { + WARN("Ignoring very long library path: %s/%s\n", *path, name); + continue; + } if ((fd = _open_lib(buf)) >= 0) return fd; } @@ -1683,6 +1701,29 @@ fail: return -1; } +static void parse_library_path(char *path, char *delim) +{ + size_t len; + char *ldpaths_bufp = ldpaths_buf; + int i = 0; + + len = strlcpy(ldpaths_buf, path, sizeof(ldpaths_buf)); + + while (i < LDPATH_MAX && (ldpaths[i] = strsep(&ldpaths_bufp, delim))) { + if (*ldpaths[i] != '\0') + ++i; + } + + /* Forget the last path if we had to truncate; this occurs if the 2nd to + * last char isn't '\0' (i.e. not originally a delim). */ + if (i > 0 && len >= sizeof(ldpaths_buf) && + ldpaths_buf[sizeof(ldpaths_buf) - 2] != '\0') { + ldpaths[i - 1] = NULL; + } else { + ldpaths[i] = NULL; + } +} + int main(int argc, char **argv) { return 0; @@ -1701,6 +1742,7 @@ unsigned __linker_init(unsigned **elfdata) unsigned *vecs = (unsigned*) (argv + argc + 1); soinfo *si; struct link_map * map; + char *ldpath_env = NULL; pid = getpid(); @@ -1718,6 +1760,8 @@ unsigned __linker_init(unsigned **elfdata) while(vecs[0] != 0) { if(!strncmp((char*) vecs[0], "DEBUG=", 6)) { debug_verbosity = atoi(((char*) vecs[0]) + 6); + } else if(!strncmp((char*) vecs[0], "LD_LIBRARY_PATH=", 16)) { + ldpath_env = (char*) vecs[0] + 16; } vecs++; } @@ -1777,6 +1821,10 @@ unsigned __linker_init(unsigned **elfdata) si->wrprotect_start = 0xffffffff; si->wrprotect_end = 0; + /* Use LD_LIBRARY_PATH if we aren't setuid/setgid */ + if (ldpath_env && getuid() == geteuid() && getgid() == getegid()) + parse_library_path(ldpath_env, ":"); + if(link_image(si, 0)) { char errmsg[] = "CANNOT LINK EXECUTABLE\n"; write(2, __linker_dl_err_buf, strlen(__linker_dl_err_buf)); |