Commit 4ced4cf5 authored by Andrei Vagin's avatar Andrei Vagin Committed by Kees Cook
Browse files

binfmt_elf_fdpic: fix AUXV size calculation for ELF_HWCAP3 and ELF_HWCAP4 



Commit 4e6e8c2b ("binfmt_elf: Wire up AT_HWCAP3 at AT_HWCAP4") added
support for AT_HWCAP3 and AT_HWCAP4, but it missed updating the AUX
vector size calculation in create_elf_fdpic_tables() and
AT_VECTOR_SIZE_BASE in include/linux/auxvec.h.

Similar to the fix for AT_HWCAP2 in commit c6a09e34 ("binfmt_elf_fdpic:
fix AUXV size calculation when ELF_HWCAP2 is defined"), this omission
leads to a mismatch between the reserved space and the actual number of
AUX entries, eventually triggering a kernel BUG_ON(csp != sp).

Fix this by incrementing nitems when ELF_HWCAP3 or ELF_HWCAP4 are
defined and updating AT_VECTOR_SIZE_BASE.

Cc: Mark Brown <broonie@kernel.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Reviewed-by: default avatarMichal Koutný <mkoutny@suse.com>
Reviewed-by: default avatarMark Brown <broonie@kernel.org>
Reviewed-by: default avatarCyrill Gorcunov <gorcunov@gmail.com>
Reviewed-by: default avatarAlexander Mikhalitsyn <aleksandr.mikhalitsyn@futurfusion.io>
Fixes: 4e6e8c2b ("binfmt_elf: Wire up AT_HWCAP3 at AT_HWCAP4")
Signed-off-by: default avatarAndrei Vagin <avagin@google.com>
Link: https://patch.msgid.link/20260217180108.1420024-2-avagin@google.com


Signed-off-by: default avatarKees Cook <kees@kernel.org>
parent 6de23f81

fs/binfmt_elf_fdpic.c

+6 −0
Original line number Diff line number Diff line
@@ -595,6 +595,12 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm, 
#ifdef ELF_HWCAP2

	nitems++;

#endif

#ifdef ELF_HWCAP3

	nitems++;

#endif

#ifdef ELF_HWCAP4

	nitems++;

#endif



	csp = sp;

	sp -= nitems * 2 * sizeof(unsigned long);

include/linux/auxvec.h

+1 −1
Original line number Diff line number Diff line
@@ -4,6 +4,6 @@ 


#include <uapi/linux/auxvec.h>



#define AT_VECTOR_SIZE_BASE 22 /* NEW_AUX_ENT entries in auxiliary table */

#define AT_VECTOR_SIZE_BASE 24 /* NEW_AUX_ENT entries in auxiliary table */

  /* number of "#define AT_.*" above, minus {AT_NULL, AT_IGNORE, AT_NOTELF} */

#endif /* _LINUX_AUXVEC_H */