From ce9a68c57c260c8417afc93972849ac9ad243ec4 Mon Sep 17 00:00:00 2001 From: Ben Woodard Date: Mon, 24 Jan 2022 10:46:18 -0300 Subject: elf: Fix runtime linker auditing on aarch64 (BZ #26643) The rtld audit support show two problems on aarch64: 1. _dl_runtime_resolve does not preserve x8, the indirect result location register, which might generate wrong result calls depending of the function signature. 2. The NEON Q registers pushed onto the stack by _dl_runtime_resolve were twice the size of D registers extracted from the stack frame by _dl_runtime_profile. While 2. might result in wrong information passed on the PLT tracing, 1. generates wrong runtime behaviour. The aarch64 rtld audit support is changed to: * Both La_aarch64_regs and La_aarch64_retval are expanded to include both x8 and the full sized NEON V registers, as defined by the ABI. * dl_runtime_profile needed to extract registers saved by _dl_runtime_resolve and put them into the new correctly sized La_aarch64_regs structure. * The LAV_CURRENT check is change to only accept new audit modules to avoid the undefined behavior of not save/restore x8. * Different than other architectures, audit modules older than LAV_CURRENT are rejected (both La_aarch64_regs and La_aarch64_retval changed their layout and there are no requirements to support multiple audit interface with the inherent aarch64 issues). * A new field is also reserved on both La_aarch64_regs and La_aarch64_retval to support variant pcs symbols. Similar to x86, a new La_aarch64_vector type to represent the NEON register is added on the La_aarch64_regs (so each type can be accessed directly). Since LAV_CURRENT was already bumped to support bind-now, there is no need to increase it again. Checked on aarch64-linux-gnu. Co-authored-by: Adhemerval Zanella Reviewed-by: Szabolcs Nagy Reviewed-by: Carlos O'Donell Tested-by: Carlos O'Donell --- elf/rtld.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'elf/rtld.c') diff --git a/elf/rtld.c b/elf/rtld.c index 10436f7034..8dafaf61f4 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -52,6 +52,7 @@ #include #include #include +#include #include @@ -1000,7 +1001,7 @@ file=%s [%lu]; audit interface function la_version returned zero; ignored.\n", return; } - if (lav > LAV_CURRENT) + if (!_dl_audit_check_version (lav)) { _dl_debug_printf ("\ ERROR: audit interface '%s' requires version %d (maximum supported version %d); ignored.\n", -- cgit 1.4.1