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| author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2024-02-05 16:10:24 +0000 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2024-02-05 15:29:23 -0300 |
| commit | 1e25112dc0cb2515d27d8d178b1ecce778a9d37a (patch) | |
| tree | d1c9369f35fdda497d93c186c92e4a7e529dab0e | |
| parent | 2e80f139376450acdb7d879d799439578a41810e (diff) | |
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arm: Remove wrong ldr from _dl_start_user (BZ 31339)
The commit 49d877a80b29d3002887b084eec6676d9f5fec18 (arm: Remove
_dl_skip_args usage) removed the _SKIP_ARGS literal, which was
previously loader to r4 on loader _start. However, the cleanup did not
remove the following 'ldr r4, [sl, r4]' on _dl_start_user, used to check
to skip the arguments after ld self-relocations.
In my testing, the kernel initially set r4 to 0, which makes the
ldr instruction just read the _GLOBAL_OFFSET_TABLE_. However, since r4
is a callee-saved register; a different runtime might not zero
initialize it and thus trigger an invalid memory access.
Checked on arm-linux-gnu.
Reported-by: Adrian Ratiu <adrian.ratiu@collabora.com>
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
| -rw-r--r-- | sysdeps/arm/dl-machine.h | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/sysdeps/arm/dl-machine.h b/sysdeps/arm/dl-machine.h index b857bbc868..dd1a0f6b6e 100644 --- a/sysdeps/arm/dl-machine.h +++ b/sysdeps/arm/dl-machine.h @@ -139,7 +139,6 @@ _start:\n\ _dl_start_user:\n\ adr r6, .L_GET_GOT\n\ add sl, sl, r6\n\ - ldr r4, [sl, r4]\n\ @ save the entry point in another register\n\ mov r6, r0\n\ @ get the original arg count\n\ |