libsframe asan: avoid generating misaligned loads

There are two places where unaligned loads were seen on aarch64:
  - #1. access to the SFrame FRE stack offsets in the in-memory
    representation/abstraction provided by libsframe.
  - #2. access to the SFrame FRE start address in the on-disk representation
    of the frame row entry.

For #1, we can fix this by reordering the struct members of
sframe_frame_row_entry in libsframe/sframe-api.h.

For #2, we need to default to using memcpy instead, and copy out the bytes
to a location for output.

SFrame format is an unaligned on-disk format. As such, there are other blobs
of memory in the on-disk SFrame FRE that are on not on their natural
boundaries.  But that does not pose further problems yet, because the users
are provided access to the on-disk SFrame FRE data via libsframe's
sframe_frame_row_entry, the latter has its' struct members aligned on their
respective natural boundaries (and initialized using memcpy).

PR 29856 libsframe asan: load misaligned at sframe.c:516

ChangeLog:

	PR libsframe/29856
	* bfd/elf64-x86-64.c: Adjust as the struct members have been
	reordered.
	* libsframe/sframe.c (sframe_decode_fre_start_address): Use
	memcpy to perform 16-bit/32-bit reads.
	* libsframe/testsuite/libsframe.encode/encode-1.c: Adjust as the
	struct members have been reordered.

include/ChangeLog:

	PR libsframe/29856
	* sframe-api.h: Reorder fre_offsets for natural alignment.

1 files changed, 12 insertions, 12 deletions

diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index afc8c76c52b..8cf733d89e0 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -822,48 +822,48 @@ static const bfd_byte elf_x86_64_eh_frame_non_lazy_plt[] =
 static const sframe_frame_row_entry elf_x86_64_sframe_null_fre =
 {
   0,
-  SFRAME_V1_FRE_INFO (SFRAME_BASE_REG_SP, 1, SFRAME_FRE_OFFSET_1B), /* FRE info.  */
-  {16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} /* 12 bytes.  */
+  {16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, /* 12 bytes.  */
+  SFRAME_V1_FRE_INFO (SFRAME_BASE_REG_SP, 1, SFRAME_FRE_OFFSET_1B) /* FRE info.  */
 };
 
 /* .sframe FRE covering the .plt section entry.  */
 static const sframe_frame_row_entry elf_x86_64_sframe_plt0_fre1 =
 {
   0, /* SFrame FRE start address.  */
-  SFRAME_V1_FRE_INFO (SFRAME_BASE_REG_SP, 1, SFRAME_FRE_OFFSET_1B), /* FRE info.  */
-  {16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} /* 12 bytes.  */
+  {16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, /* 12 bytes.  */
+  SFRAME_V1_FRE_INFO (SFRAME_BASE_REG_SP, 1, SFRAME_FRE_OFFSET_1B) /* FRE info.  */
 };
 
 /* .sframe FRE covering the .plt section entry.  */
 static const sframe_frame_row_entry elf_x86_64_sframe_plt0_fre2 =
 {
   6, /* SFrame FRE start address.  */
-  SFRAME_V1_FRE_INFO (SFRAME_BASE_REG_SP, 1, SFRAME_FRE_OFFSET_1B), /* FRE info.  */
-  {24, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} /* 12 bytes.  */
+  {24, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, /* 12 bytes.  */
+  SFRAME_V1_FRE_INFO (SFRAME_BASE_REG_SP, 1, SFRAME_FRE_OFFSET_1B) /* FRE info.  */
 };
 
 /* .sframe FRE covering the .plt section entry.  */
 static const sframe_frame_row_entry elf_x86_64_sframe_pltn_fre1 =
 {
   0, /* SFrame FRE start address.  */
-  SFRAME_V1_FRE_INFO (SFRAME_BASE_REG_SP, 1, SFRAME_FRE_OFFSET_1B), /* FRE info.  */
-  {8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} /* 12 bytes.  */
+  {8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, /* 12 bytes.  */
+  SFRAME_V1_FRE_INFO (SFRAME_BASE_REG_SP, 1, SFRAME_FRE_OFFSET_1B) /* FRE info.  */
 };
 
 /* .sframe FRE covering the .plt section entry.  */
 static const sframe_frame_row_entry elf_x86_64_sframe_pltn_fre2 =
 {
   11, /* SFrame FRE start address.  */
-  SFRAME_V1_FRE_INFO (SFRAME_BASE_REG_SP, 1, SFRAME_FRE_OFFSET_1B), /* FRE info.  */
-  {16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} /* 12 bytes.  */
+  {16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, /* 12 bytes.  */
+  SFRAME_V1_FRE_INFO (SFRAME_BASE_REG_SP, 1, SFRAME_FRE_OFFSET_1B) /* FRE info.  */
 };
 
 /* .sframe FRE covering the second .plt section entry.  */
 static const sframe_frame_row_entry elf_x86_64_sframe_sec_pltn_fre1 =
 {
   0, /* SFrame FRE start address.  */
-  SFRAME_V1_FRE_INFO (SFRAME_BASE_REG_SP, 1, SFRAME_FRE_OFFSET_1B), /* FRE info.  */
-  {8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} /* 12 bytes.  */
+  {8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, /* 12 bytes.  */
+  SFRAME_V1_FRE_INFO (SFRAME_BASE_REG_SP, 1, SFRAME_FRE_OFFSET_1B) /* FRE info.  */
 };
 
 /* SFrame helper object for non-lazy PLT.  Also used for IBT enabled PLT.  */