libdwfl: Call xlatetom on aligned buffers in dwfl_link_map_report
Commit Message
Make sure that when calling xlatetom for Phdrs and Dyns in
dwfl_link_map_report the input buffer is correctly aligned by calling
memcpy and setting in.d_buf to out.d_buf.
https://sourceware.org/bugzilla/show_bug.cgi?id=28720
Signed-off-by: Mark Wielaard <mark@klomp.org>
---
libdwfl/ChangeLog | 5 +++++
libdwfl/link_map.c | 19 ++++++++++++++++++-
2 files changed, 23 insertions(+), 1 deletion(-)
Comments
On Fri, Dec 24, 2021 at 01:49:54AM +0100, Mark Wielaard wrote:
> Make sure that when calling xlatetom for Phdrs and Dyns in
> dwfl_link_map_report the input buffer is correctly aligned by calling
> memcpy and setting in.d_buf to out.d_buf.
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=28720
Pushed
@@ -1,3 +1,8 @@
+2021-12-23 Mark Wielaard <mark@klomp.org>
+
+ * link_map.c (dwfl_link_map_report): Call memcpy and set in.d_buf to
+ out.d_buf before calling xlatetom for unaligned buffers.
+
2021-12-23 Mark Wielaard <mark@klomp.org>
* core-file.c (dwfl_elf_phdr_memory_callback): Check start <
@@ -922,11 +922,20 @@ dwfl_link_map_report (Dwfl *dwfl, const void *auxv, size_t auxv_size,
return false;
}
}
+ bool is32 = (elfclass == ELFCLASS32);
+ size_t phdr_align = (is32
+ ? __alignof__ (Elf32_Phdr)
+ : __alignof__ (Elf64_Phdr));
+ if (!in_from_exec
+ && ((uintptr_t) in.d_buf & (phdr_align - 1)) != 0)
+ {
+ memcpy (out.d_buf, in.d_buf, in.d_size);
+ in.d_buf = out.d_buf;
+ }
if (likely ((elfclass == ELFCLASS32
? elf32_xlatetom : elf64_xlatetom)
(&out, &in, elfdata) != NULL))
{
- bool is32 = (elfclass == ELFCLASS32);
for (size_t i = 0; i < phnum; ++i)
{
GElf_Word type = (is32
@@ -1044,6 +1053,14 @@ dwfl_link_map_report (Dwfl *dwfl, const void *auxv, size_t auxv_size,
};
if (in.d_size > out.d_size)
in.d_size = out.d_size;
+ size_t dyn_align = (elfclass == ELFCLASS32
+ ? __alignof__ (Elf32_Dyn)
+ : __alignof__ (Elf64_Dyn));
+ if (((uintptr_t) in.d_buf & (dyn_align - 1)) != 0)
+ {
+ memcpy (out.d_buf, in.d_buf, in.d_size);
+ in.d_buf = out.d_buf;
+ }
if (likely ((elfclass == ELFCLASS32
? elf32_xlatetom : elf64_xlatetom)
(&out, &in, elfdata) != NULL))