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libsframe asan: avoid generating misaligned loads

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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.
This commit is contained in:
Indu Bhagat
2022-12-15 13:12:01 -08:00
parent 69de431392
commit 8c078abdc2
4 changed files with 42 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
libsframe/testsuite/libsframe.encode/encode-1.c
View File

@@ -33,10 +33,10 @@ add_fde1 (sframe_encoder_ctx *encode, int idx)
int i, err;
/* A contiguous block containing 4 FREs. */
sframe_frame_row_entry fres[]
= { {0x0, 0x3, {0x8, 0, 0}},
{0x1, 0x5, {0x10, 0xf0, 0}},
{0x4, 0x4, {0x10, 0xf0, 0}},
{0x1a, 0x5, {0x8, 0xf0, 0}}
= { {0x0, {0x8, 0, 0}, 0x3},
{0x1, {0x10, 0xf0, 0}, 0x5},
{0x4, {0x10, 0xf0, 0}, 0x4},
{0x1a, {0x8, 0xf0, 0}, 0x5}
};
unsigned char finfo = sframe_fde_create_func_info (SFRAME_FRE_TYPE_ADDR1,
@@ -58,10 +58,10 @@ add_fde2 (sframe_encoder_ctx *encode, int idx)
int i, err;
/* A contiguous block containing 4 FREs. */
sframe_frame_row_entry fres[]
= { {0x0, 0x3, {0x8, 0, 0}},
{0x1, 0x5, {0x10, 0xf0, 0}},
{0x4, 0x4, {0x10, 0xf0, 0}},
{0xf, 0x5, {0x8, 0xf0, 0}}
= { {0x0, {0x8, 0, 0}, 0x3},
{0x1, {0x10, 0xf0, 0}, 0x5},
{0x4, {0x10, 0xf0, 0}, 0x4},
{0xf, {0x8, 0xf0, 0}, 0x5}
};
unsigned char finfo = sframe_fde_create_func_info (SFRAME_FRE_TYPE_ADDR1,