diff options
| author | Stephan Gerhold <stephan@gerhold.net> | 2018-01-24 15:13:24 +0100 |
|---|---|---|
| committer | Emil Velikov <emil.l.velikov@gmail.com> | 2018-02-05 19:06:01 +0000 |
| commit | e6018eceb91489838cc1fcbca6efd338876c4743 (patch) | |
| tree | affb11262c54b3bb13b1bf1dd7597ead210f8fbe /src/util | |
| parent | 227e0fb0a439807fc4f1930ab6a684920708601f (diff) | |
util/build-id: Fix address comparison for binaries with LOAD vaddr > 0
build_id_find_nhdr_for_addr() fails to find the build-id if the first LOAD
segment has a virtual address other than 0x0.
For most shared libraries, the first LOAD segment has vaddr=0x0:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
LOAD 0x000000 0x00000000 0x00000000 0x2d2e26 0x2d2e26 R E 0x1000
LOAD 0x2d2e54 0x002d3e54 0x002d3e54 0x2e248 0x2f148 RW 0x1000
However, compiling the Intel Vulkan driver as 32-bit binary on Android produces
the following ELF header with vaddr=0x8000 instead:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
PHDR 0x000034 0x00008034 0x00008034 0x00100 0x00100 R 0x4
LOAD 0x000000 0x00008000 0x00008000 0x224a04 0x224a04 R E 0x1000
LOAD 0x225710 0x0022e710 0x0022e710 0x25988 0x27364 RW 0x1000
build_id_find_nhdr_callback() compares the address of dli_fbase from dladdr()
and dlpi_addr from dl_iterate_phdr(). With vaddr > 0, these point to a
different memory address, e.g.:
dli_fbase=0xd8395000 (offset 0x8000)
dlpi_addr=0xd838d000
At least on glibc and bionic (Android) dli_fbase refers to the address where
the shared object is mapped into the process space, whereas dlpi_addr is just
the base address for the vaddrs declared in the ELF header.
To compare them correctly, we need to calculate the start of the mapping
by adding the vaddr of the first LOAD segment to the base address.
Note: musl users will need the following patch.
https://git.musl-libc.org/cgit/musl/commit/?id=b3ae7beabb9f0c219bb8a8b63567a01c6530c1ac
Cc: Chad Versace <chadversary@chromium.org>
Cc: <mesa-stable@lists.freedesktop.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104642
Fixes: 5c98d38 "util: Query build-id by symbol address, not library name"
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
(cherry picked from commit 02e2009b929a0f101540b9b55c5f0ed859d1b3be)
Diffstat (limited to 'src/util')
| -rw-r--r-- | src/util/build_id.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/src/util/build_id.c b/src/util/build_id.c index 536c74360e..fb67d160e3 100644 --- a/src/util/build_id.c +++ b/src/util/build_id.c @@ -58,7 +58,18 @@ build_id_find_nhdr_callback(struct dl_phdr_info *info, size_t size, void *data_) { struct callback_data *data = data_; - if ((void *)info->dlpi_addr != data->dli_fbase) + /* Calculate address where shared object is mapped into the process space. + * (Using the base address and the virtual address of the first LOAD segment) + */ + void *map_start = NULL; + for (unsigned i = 0; i < info->dlpi_phnum; i++) { + if (info->dlpi_phdr[i].p_type == PT_LOAD) { + map_start = (void *)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); + break; + } + } + + if (map_start != data->dli_fbase) return 0; for (unsigned i = 0; i < info->dlpi_phnum; i++) { |