Merge upstream

examples/Makefile

@@ -3,7 +3,6 @@ all:
 	$(CC) -O0 -g -fPIC -pie elfparse.c ../src/libelfmaster.a -o elfparse
 	$(CC) -O0 -g merged.c ../src/libelfmaster.a -o merged
 	$(CC) -O0 -g ldd.c ../src/libelfmaster.a -o ldd
-	$(CC) -O0 -g ldd2.c ../src/libelfmaster.a -o ldd2
 	$(CC) -O2 -g read_mem.c ../src/libelfmaster.a -o read_mem
 	$(CC) -O2 -g plt_dump.c ../src/libelfmaster.a -o plt_dump
 	$(CC) -O2 -g plt_dump2.c ../src/libelfmaster.a -o plt_dump2

examples/ldd.c

@@ -19,13 +19,14 @@ int main(int argc, char **argv)
 		exit(EXIT_SUCCESS);
 	}
 
-	if (elf_open_object(argv[1], &obj, ELF_LOAD_F_FORENSICS, &error) == false) {
+	if (elf_open_object(argv[1], &obj, ELF_LOAD_F_LXC_MODE|ELF_LOAD_F_FORENSICS, &error) == false) {
 		fprintf(stderr, "%s\n", elf_error_msg(&error));
 		return -1;
 	}
 
+	elf_lxc_set_rootfs(&obj, "/cont/arch/rootfs");
 	if (elf_shared_object_iterator_init(&obj, &so_iter,
-	    NULL, ELF_SO_LDSO_FAST_F|ELF_SO_IGNORE_VDSO_F|ELF_SO_RESOLVE_F, &error) == false) {
+	    "/cont/arch/rootfs/etc/ld.so.cache", /*ELF_SO_LDSO_FAST_F|ELF_SO_IGNORE_VDSO_F|*/ELF_SO_RESOLVE_F|ELF_SO_RESOLVE_ALL_F, &error) == false) {
 		fprintf(stderr, "elf_shared_object_iterator_init failed: %s\n",
 		    elf_error_msg(&error));
 		return -1;

include/libelfmaster.h

@@ -86,6 +86,8 @@
 #define ELF_ERRNO_INVALMAGIC	0
 #define ELF_ERRNO_INVALSHDRS	1
 
+#define ELF_LXC_ROOTFS_VAR "LXC_ROOTFS_VAR_LIBELFMASTER"
+
 typedef struct elf_error {
 	char string[MAX_ERROR_STR_LEN];
 	int _errno;
@@ -560,6 +562,7 @@ typedef struct elf_shared_object_iterator {
 #define ELF_LOAD_F_MODIFY	(1UL << 3) //Used for modifying binaries
 #define ELF_LOAD_F_ULEXEC	(1UL << 4) //Used for ulexec based debugging API
 #define ELF_LOAD_F_MAP_WRITE	(1UL << 5)
+#define ELF_LOAD_F_LXC_MODE	(1UL << 6) // Used when scanning binaries within an LXC container
 
 /*
  * Loads an ELF object of any type, for reading or modifying.
@@ -977,4 +980,13 @@ bool elf_dynsym_commit(elfobj_t *);
  * freeing the existing internal representation and then sorting a new array of strings.
  */
 bool elf_section_commit(elfobj_t *);
+
+/*
+ * Set the environment variable that libelfmaster reads to get
+ * the LXC containers rootfs in order to resolve shared libaries
+ * from this location internally.
+ */
+bool elf_lxc_set_rootfs(elfobj_t *, const char *);
+bool elf_lxc_get_rootfs(elfobj_t *, char *, const size_t);
+
 #endif

src/internal.c

@@ -42,6 +42,8 @@
 #include "dwarf.h"
 #include "misc.h"
 
+static char *
+ldso_strdup(struct elf_shared_object_iterator *, const char *);
 
 /*
  * TODO Why is this defined in internal.c?
@@ -508,6 +510,18 @@ ldso_cache_bsearch(struct elf_shared_object_iterator *iter,
 			right = middle - 1;
 		}
 	}
+
+	if (iter->obj->load_flags & ELF_LOAD_F_LXC_MODE) {
+		char lxc_path[PATH_MAX];
+
+		if (elf_lxc_get_rootfs(iter->obj, lxc_path, PATH_MAX / 2) == false) {
+			if (strlen(lxc_path) + strlen(best) >= PATH_MAX)
+				return false;
+		}
+		strcat(lxc_path, best);
+		best = ldso_strdup(iter, lxc_path);
+	}
+
 	return best;
 }
 
@@ -660,10 +674,9 @@ ldso_recursive_cache_resolve(struct elf_shared_object_iterator *iter,
 		 * object iterator will use the linked list cache.
 		 */
 		current->path = ldso_strdup(iter, path);
-		if (current->path == NULL) {
+		if (current->path == NULL)
 			goto err;
-		}
-		if (ldso_insert_yield_entry(iter, current->path) == false){
+		if (ldso_insert_yield_entry(iter, current->path) == false) {
 			goto err;
 		}
 		if (ldso_recursive_cache_resolve(iter, current->basename) == false){

src/libelfmaster.c

@@ -54,6 +54,33 @@
 	(((addr) + __alignof__ (struct cache_file_new) -1)	\
 	    & (~(__alignof__ (struct cache_file_new) - 1)))
 
+bool
+elf_lxc_set_rootfs(elfobj_t *obj, const char *lxcpath)
+{
+	if ((obj->load_flags & ELF_LOAD_F_LXC_MODE) == false) {
+		return true;
+	}
+	if (setenv(ELF_LXC_ROOTFS_VAR, lxcpath, 1) == 0)
+		return true;
+	return false;
+}
+
+bool
+elf_lxc_get_rootfs(elfobj_t *obj, char *out, const size_t maxlen)
+{
+	char *v = secure_getenv(ELF_LXC_ROOTFS_VAR);
+
+	(void) obj;
+
+	if (maxlen > PATH_MAX)
+		return false;
+	if (strlen(v) > maxlen - 1)
+		return false;
+	strncpy(out, v, maxlen);
+	out[maxlen - 1] = '\0';
+	return true;
+}
+
 bool
 elf_symtab_count(elfobj_t *obj, uint64_t *count)
 {
@@ -1520,17 +1547,17 @@ elf_shared_object_iterator_init(struct elfobj *obj,
 	}
 	iter->fd = open(cache_file, O_RDONLY);
 	if (iter->fd < 0) {
-		return elf_error_set(error, "open %s: %s", CACHE_FILE,
+		return elf_error_set(error, "open %s: %s", cache_file,
 		    strerror(errno));
 	}
 	if (fstat(iter->fd, &iter->st) < 0) {
-		return elf_error_set(error, "fstat %s: %s", CACHE_FILE,
+		return elf_error_set(error, "fstat %s: %s", cache_file,
 		    strerror(errno));
 	}
 	iter->mem = mmap(NULL, iter->st.st_size, PROT_READ, MAP_PRIVATE,
 	    iter->fd, 0);
 	if (iter->mem == MAP_FAILED) {
-		return elf_error_set(error, "mmap %s: %s", CACHE_FILE,
+		return elf_error_set(error, "mmap %s: %s", cache_file,
 		    strerror(errno));
 	}
 	iter->cache = iter->mem;