Read the elf file pointed at by the .gnu_debugaltlink section, and verify that
the build id matches.
2018-11-11 Tom de Vries <tdevr...@suse.de>
* elf.c (elf_add): Add and handle with_buildid_data and
with_buildid_size parameters. Handle .gnu_debugaltlink section.
(phdr_callback, backtrace_initialize): Add arguments to elf_add calls.
---
libbacktrace/elf.c | 95 +++++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 90 insertions(+), 5 deletions(-)
diff --git a/libbacktrace/elf.c b/libbacktrace/elf.c
index f4863f0bea5..f3bc2119c07 100644
--- a/libbacktrace/elf.c
+++ b/libbacktrace/elf.c
@@ -2638,7 +2638,8 @@ static int
elf_add (struct backtrace_state *state, const char *filename, int descriptor,
uintptr_t base_address, backtrace_error_callback error_callback,
void *data, fileline *fileline_fn, int *found_sym, int *found_dwarf,
- int exe, int debuginfo)
+ int exe, int debuginfo, const char *with_buildid_data,
+ uint32_t with_buildid_size)
{
struct backtrace_view ehdr_view;
b_elf_ehdr ehdr;
@@ -2670,6 +2671,11 @@ elf_add (struct backtrace_state *state, const char
*filename, int descriptor,
int debuglink_view_valid;
const char *debuglink_name;
uint32_t debuglink_crc;
+ struct backtrace_view debugaltlink_view;
+ int debugaltlink_view_valid;
+ const char *debugaltlink_name;
+ const char *debugaltlink_buildid_data;
+ uint32_t debugaltlink_buildid_size;
off_t min_offset;
off_t max_offset;
struct backtrace_view debug_view;
@@ -2694,6 +2700,10 @@ elf_add (struct backtrace_state *state, const char
*filename, int descriptor,
debuglink_view_valid = 0;
debuglink_name = NULL;
debuglink_crc = 0;
+ debugaltlink_view_valid = 0;
+ debugaltlink_name = NULL;
+ debugaltlink_buildid_data = NULL;
+ debugaltlink_buildid_size = 0;
debug_view_valid = 0;
opd = NULL;
@@ -2873,6 +2883,15 @@ elf_add (struct backtrace_state *state, const char
*filename, int descriptor,
buildid_data = ¬e->name[0] + ((note->namesz + 3) & ~ 3);
buildid_size = note->descsz;
}
+
+ if (with_buildid_size != 0)
+ {
+ if (buildid_size != with_buildid_size)
+ goto fail;
+
+ if (memcmp (buildid_data, with_buildid_data, buildid_size) != 0)
+ goto fail;
+ }
}
/* Read the debuglink file if present. */
@@ -2899,6 +2918,27 @@ elf_add (struct backtrace_state *state, const char
*filename, int descriptor,
}
}
+ if (!debugaltlink_view_valid
+ && strcmp (name, ".gnu_debugaltlink") == 0)
+ {
+ const char *debugaltlink_data;
+ size_t debugaltlink_name_len;
+
+ if (!backtrace_get_view (state, descriptor, shdr->sh_offset,
+ shdr->sh_size, error_callback, data,
+ &debugaltlink_view))
+ goto fail;
+
+ debugaltlink_view_valid = 1;
+ debugaltlink_data = (const char *) debugaltlink_view.data;
+ debugaltlink_name = debugaltlink_data;
+ debugaltlink_name_len = strnlen (debugaltlink_data, shdr->sh_size);
+ debugaltlink_buildid_data = (debugaltlink_data
+ + debugaltlink_name_len
+ + 1);
+ debugaltlink_buildid_size = shdr->sh_size - debugaltlink_name_len - 1;
+ }
+
/* Read the .opd section on PowerPC64 ELFv1. */
if (ehdr.e_machine == EM_PPC64
&& (ehdr.e_flags & EF_PPC64_ABI) < 2
@@ -2993,8 +3033,11 @@ elf_add (struct backtrace_state *state, const char
*filename, int descriptor,
if (debuglink_view_valid)
backtrace_release_view (state, &debuglink_view, error_callback,
data);
+ if (debugaltlink_view_valid)
+ backtrace_release_view (state, &debugaltlink_view, error_callback,
+ data);
ret = elf_add (state, NULL, d, base_address, error_callback, data,
- fileline_fn, found_sym, found_dwarf, 0, 1);
+ fileline_fn, found_sym, found_dwarf, 0, 1, NULL, 0);
if (ret < 0)
backtrace_close (d, error_callback, data);
else
@@ -3028,8 +3071,11 @@ elf_add (struct backtrace_state *state, const char
*filename, int descriptor,
backtrace_release_view (state, &debuglink_view, error_callback,
data);
+ if (debugaltlink_view_valid)
+ backtrace_release_view (state, &debugaltlink_view, error_callback,
+ data);
ret = elf_add (state, NULL, d, base_address, error_callback, data,
- fileline_fn, found_sym, found_dwarf, 0, 1);
+ fileline_fn, found_sym, found_dwarf, 0, 1, NULL, 0);
if (ret < 0)
backtrace_close (d, error_callback, data);
else
@@ -3044,6 +3090,43 @@ elf_add (struct backtrace_state *state, const char
*filename, int descriptor,
debuglink_view_valid = 0;
}
+ if (debugaltlink_name != NULL)
+ {
+ int d;
+
+ d = elf_open_debugfile_by_debuglink (state, filename, debugaltlink_name,
+ 0, error_callback, data);
+ if (d >= 0)
+ {
+ int ret;
+
+ ret = elf_add (state, filename, d, base_address, error_callback, data,
+ fileline_fn, found_sym, found_dwarf, 0, 1,
+ debugaltlink_buildid_data, debugaltlink_buildid_size);
+ backtrace_release_view (state, &debugaltlink_view, error_callback,
+ data);
+ debugaltlink_view_valid = 0;
+ if (ret < 0)
+ {
+ backtrace_close (d, error_callback, data);
+ return ret;
+ }
+ }
+ else
+ {
+ error_callback (data,
+ "Could not open .gnu_debugaltlink", 0);
+ /* Don't goto fail, but try continue without the info in the
+ .gnu_debugaltlink. */
+ }
+ }
+
+ if (debugaltlink_view_valid)
+ {
+ backtrace_release_view (state, &debugaltlink_view, error_callback, data);
+ debugaltlink_view_valid = 0;
+ }
+
/* Read all the debug sections in a single view, since they are
probably adjacent in the file. We never release this view. */
@@ -3199,6 +3282,8 @@ elf_add (struct backtrace_state *state, const char
*filename, int descriptor,
backtrace_release_view (state, &strtab_view, error_callback, data);
if (debuglink_view_valid)
backtrace_release_view (state, &debuglink_view, error_callback, data);
+ if (debugaltlink_view_valid)
+ backtrace_release_view (state, &debugaltlink_view, error_callback, data);
if (buildid_view_valid)
backtrace_release_view (state, &buildid_view, error_callback, data);
if (debug_view_valid)
@@ -3269,7 +3354,7 @@ phdr_callback (struct dl_phdr_info *info, size_t size
ATTRIBUTE_UNUSED,
if (elf_add (pd->state, filename, descriptor, info->dlpi_addr,
pd->error_callback, pd->data, &elf_fileline_fn, pd->found_sym,
- &found_dwarf, 0, 0))
+ &found_dwarf, 0, 0, NULL, 0))
{
if (found_dwarf)
{
@@ -3297,7 +3382,7 @@ backtrace_initialize (struct backtrace_state *state,
const char *filename,
struct phdr_data pd;
ret = elf_add (state, filename, descriptor, 0, error_callback, data,
- &elf_fileline_fn, &found_sym, &found_dwarf, 1, 0);
+ &elf_fileline_fn, &found_sym, &found_dwarf, 1, 0, NULL, 0);
if (!ret)
return 0;
--
2.16.4
