#define TEXT_SECTION_NAME ".text"
#define SYMBOL_TAB_SECTION_NAME ".symtab"
#define STRING_TAB_SECTION_NAME ".strtab"
+#define DYNAMIC_SYMBOL_TAB_SECTION_NAME ".dynsym"
+#define DYNAMIC_STRING_TAB_SECTION_NAME ".dynstr"
#define NOTE_STAPSDT_SECTION_NAME ".note.stapsdt"
#define NOTE_STAPSDT_NAME "stapsdt"
#define NOTE_STAPSDT_TYPE 3
+#define MAX_SECTION_DATA_SIZE 512 * 1024 * 1024
#if BYTE_ORDER == LITTLE_ENDIAN
#define NATIVE_ELF_ENDIANNESS ELFDATA2LSB
do { \
switch (sizeof(x)) { \
case 8: \
- x = be64toh(x); \
+ x = be64toh((uint64_t)x); \
break; \
case 4: \
- x = be32toh(x); \
+ x = be32toh((uint32_t)x); \
break; \
case 2: \
- x = be16toh(x); \
+ x = be16toh((uint16_t)x); \
break; \
case 1: \
break; \
struct lttng_elf {
int fd;
+ size_t file_size;
uint8_t bitness;
uint8_t endianness;
/* Offset in bytes to start of section names string table. */
* Retrieve the nth (where n is the `index` argument) shdr (section
* header) from the given elf instance.
*
- * A pointer to the shdr is returned on success, NULL on failure.
+ * 0 is returned on succes, -1 on failure.
*/
static
-struct lttng_elf_shdr *lttng_elf_get_section_hdr(struct lttng_elf *elf,
- uint16_t index)
+int lttng_elf_get_section_hdr(struct lttng_elf *elf,
+ uint16_t index, struct lttng_elf_shdr *out_header)
{
- struct lttng_elf_shdr *section_header = NULL;
int ret = 0;
if (!elf) {
+ ret = -1;
goto error;
}
if (index >= elf->ehdr->e_shnum) {
+ ret = -1;
goto error;
}
- section_header = zmalloc(sizeof(struct lttng_elf_shdr));
- if (!section_header) {
- goto error;
- }
-
- ret = populate_section_header(elf, section_header, index);
+ ret = populate_section_header(elf, out_header, index);
if (ret) {
- ret = LTTNG_ERR_ELF_PARSING;
DBG("Error populating section header.");
goto error;
}
- return section_header;
error:
- free(section_header);
- return NULL;
+ return ret;
}
/*
static
struct lttng_elf *lttng_elf_create(int fd)
{
- struct lttng_elf_shdr *section_names_shdr;
+ struct lttng_elf_shdr section_names_shdr;
struct lttng_elf *elf = NULL;
int ret;
+ struct stat stat_buf;
if (fd < 0) {
goto error;
}
+ ret = fstat(fd, &stat_buf);
+ if (ret) {
+ PERROR("Failed to determine size of elf file");
+ goto error;
+ }
+ if (!S_ISREG(stat_buf.st_mode)) {
+ ERR("Refusing to initialize lttng_elf from non-regular file");
+ goto error;
+ }
+
elf = zmalloc(sizeof(struct lttng_elf));
if (!elf) {
PERROR("Error allocating struct lttng_elf");
goto error;
}
+ elf->file_size = (size_t) stat_buf.st_size;
elf->fd = dup(fd);
if (elf->fd < 0) {
goto error;
}
- section_names_shdr = lttng_elf_get_section_hdr(elf, elf->ehdr->e_shstrndx);
- if (!section_names_shdr) {
+ ret = lttng_elf_get_section_hdr(
+ elf, elf->ehdr->e_shstrndx, §ion_names_shdr);
+ if (ret) {
goto error;
}
- elf->section_names_offset = section_names_shdr->sh_offset;
- elf->section_names_size = section_names_shdr->sh_size;
-
- free(section_names_shdr);
+ elf->section_names_offset = section_names_shdr.sh_offset;
+ elf->section_names_size = section_names_shdr.sh_size;
return elf;
error:
static
int lttng_elf_get_section_hdr_by_name(struct lttng_elf *elf,
- const char *section_name, struct lttng_elf_shdr **section_hdr)
+ const char *section_name, struct lttng_elf_shdr *section_hdr)
{
int i;
char *curr_section_name;
+
for (i = 0; i < elf->ehdr->e_shnum; ++i) {
- *section_hdr = lttng_elf_get_section_hdr(elf, i);
- curr_section_name = lttng_elf_get_section_name(elf,
- (*section_hdr)->sh_name);
+ bool name_equal;
+ int ret = lttng_elf_get_section_hdr(elf, i, section_hdr);
+ if (ret) {
+ break;
+ }
+ curr_section_name = lttng_elf_get_section_name(elf,
+ section_hdr->sh_name);
if (!curr_section_name) {
continue;
}
- if (strcmp(curr_section_name, section_name) == 0) {
+ name_equal = strcmp(curr_section_name, section_name) == 0;
+ free(curr_section_name);
+ if (name_equal) {
return 0;
}
}
int ret;
off_t section_offset;
char *data;
+ size_t max_alloc_size;
if (!elf || !shdr) {
goto error;
}
+ max_alloc_size = min_t(size_t, MAX_SECTION_DATA_SIZE, elf->file_size);
+
section_offset = shdr->sh_offset;
if (lseek(elf->fd, section_offset, SEEK_SET) < 0) {
PERROR("Error seeking to section offset");
goto error;
}
+ if (shdr->sh_size > max_alloc_size) {
+ ERR("ELF section size exceeds maximal allowed size of %zu bytes",
+ max_alloc_size);
+ goto error;
+ }
data = zmalloc(shdr->sh_size);
if (!data) {
PERROR("Error allocating buffer for ELF section data");
off_t text_section_addr_beg;
off_t text_section_addr_end;
off_t offset_in_section;
- struct lttng_elf_shdr *text_section_hdr = NULL;
+ struct lttng_elf_shdr text_section_hdr;
if (!elf_handle) {
DBG("Invalid ELF handle.");
goto error;
}
- text_section_offset = text_section_hdr->sh_offset;
- text_section_addr_beg = text_section_hdr->sh_addr;
- text_section_addr_end = text_section_addr_beg + text_section_hdr->sh_size;
+ text_section_offset = text_section_hdr.sh_offset;
+ text_section_addr_beg = text_section_hdr.sh_addr;
+ text_section_addr_end =
+ text_section_addr_beg + text_section_hdr.sh_size;
/*
* Verify that the address is within the .text section boundaries.
char *curr_sym_str = NULL;
char *symbol_table_data = NULL;
char *string_table_data = NULL;
- struct lttng_elf_shdr *symtab_hdr = NULL;
- struct lttng_elf_shdr *strtab_hdr = NULL;
+ char *string_table_name = NULL;
+ struct lttng_elf_shdr symtab_hdr;
+ struct lttng_elf_shdr strtab_hdr;
struct lttng_elf *elf = NULL;
if (!symbol || !offset ) {
goto end;
}
- /* Get the symbol table section header. */
+ /*
+ * The .symtab section might not exist on stripped binaries.
+ * Try to get the symbol table section header first. If it's absent,
+ * try to get the dynamic symbol table. All symbols in the dynamic
+ * symbol tab are in the (normal) symbol table if it exists.
+ */
ret = lttng_elf_get_section_hdr_by_name(elf, SYMBOL_TAB_SECTION_NAME,
&symtab_hdr);
if (ret) {
- DBG("Cannot get ELF Symbol Table section.");
- ret = LTTNG_ERR_ELF_PARSING;
- goto destroy_elf;
+ DBG("Cannot get ELF Symbol Table section. Trying to get ELF Dynamic Symbol Table section.");
+ /* Get the dynamic symbol table section header. */
+ ret = lttng_elf_get_section_hdr_by_name(elf, DYNAMIC_SYMBOL_TAB_SECTION_NAME,
+ &symtab_hdr);
+ if (ret) {
+ DBG("Cannot get ELF Symbol Table nor Dynamic Symbol Table sections.");
+ ret = LTTNG_ERR_ELF_PARSING;
+ goto destroy_elf;
+ }
+ string_table_name = DYNAMIC_STRING_TAB_SECTION_NAME;
+ } else {
+ string_table_name = STRING_TAB_SECTION_NAME;
}
+
/* Get the data associated with the symbol table section. */
- symbol_table_data = lttng_elf_get_section_data(elf, symtab_hdr);
+ symbol_table_data = lttng_elf_get_section_data(elf, &symtab_hdr);
if (symbol_table_data == NULL) {
DBG("Cannot get ELF Symbol Table data.");
ret = LTTNG_ERR_ELF_PARSING;
}
/* Get the string table section header. */
- ret = lttng_elf_get_section_hdr_by_name(elf, STRING_TAB_SECTION_NAME,
+ ret = lttng_elf_get_section_hdr_by_name(elf, string_table_name,
&strtab_hdr);
if (ret) {
DBG("Cannot get ELF string table section.");
}
/* Get the data associated with the string table section. */
- string_table_data = lttng_elf_get_section_data(elf, strtab_hdr);
+ string_table_data = lttng_elf_get_section_data(elf, &strtab_hdr);
if (string_table_data == NULL) {
DBG("Cannot get ELF string table section data.");
ret = LTTNG_ERR_ELF_PARSING;
}
/* Get the number of symbol in the table for the iteration. */
- sym_count = symtab_hdr->sh_size / symtab_hdr->sh_entsize;
+ sym_count = symtab_hdr.sh_size / symtab_hdr.sh_entsize;
/* Loop over all symbol. */
for (sym_idx = 0; sym_idx < sym_count; sym_idx++) {
*/
ret = lttng_elf_convert_addr_in_text_to_offset(elf, addr, offset);
if (ret) {
- DBG("Cannot convet addr to offset.");
+ DBG("Cannot convert addr to offset.");
goto free_string_table_data;
}
const char *probe_name, uint64_t **offsets, uint32_t *nb_probes)
{
int ret = 0, nb_match = 0;
- struct lttng_elf_shdr *stap_note_section_hdr = NULL;
+ struct lttng_elf_shdr stap_note_section_hdr;
struct lttng_elf *elf = NULL;
char *stap_note_section_data = NULL;
char *curr_note_section_begin, *curr_data_ptr, *curr_probe, *curr_provider;
}
/* Get the data associated with the stap note section. */
- stap_note_section_data = lttng_elf_get_section_data(elf, stap_note_section_hdr);
+ stap_note_section_data =
+ lttng_elf_get_section_data(elf, &stap_note_section_hdr);
if (stap_note_section_data == NULL) {
DBG("Cannot get ELF stap note section data.");
ret = LTTNG_ERR_ELF_PARSING;
goto destroy_elf_error;
}
- curr_data_ptr = stap_note_section_data;
next_note_ptr = stap_note_section_data;
curr_note_section_begin = stap_note_section_data;
curr_data_ptr = next_note_ptr;
/* Check if we have reached the end of the note section. */
if (curr_data_ptr >=
- curr_note_section_begin + stap_note_section_hdr->sh_size) {
+ curr_note_section_begin +
+ stap_note_section_hdr.sh_size) {
*nb_probes = nb_match;
*offsets = probe_locs;
ret = 0;
projects / lttng-tools.git / blobdiff