@@ -312,6 +312,7 @@ do { \
NEW_AUX_ENT(AT_SYSINFO, VDSO_ENTRY); \
NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_CURRENT_BASE); \
} \
+ NEW_AUX_ENT(AT_MINSIGSTKSZ, get_sigframe_size()); \
} while (0)
/*
@@ -328,6 +329,7 @@ extern unsigned long task_size_32bit(void);
extern unsigned long task_size_64bit(int full_addr_space);
extern unsigned long get_mmap_base(int is_legacy);
extern bool mmap_address_hint_valid(unsigned long addr, unsigned long len);
+extern unsigned long get_sigframe_size(void);
#ifdef CONFIG_X86_32
@@ -349,6 +351,7 @@ do { \
if (vdso64_enabled) \
NEW_AUX_ENT(AT_SYSINFO_EHDR, \
(unsigned long __force)current->mm->context.vdso); \
+ NEW_AUX_ENT(AT_MINSIGSTKSZ, get_sigframe_size()); \
} while (0)
/* As a historical oddity, the x32 and x86_64 vDSOs are controlled together. */
@@ -357,6 +360,7 @@ do { \
if (vdso64_enabled) \
NEW_AUX_ENT(AT_SYSINFO_EHDR, \
(unsigned long __force)current->mm->context.vdso); \
+ NEW_AUX_ENT(AT_MINSIGSTKSZ, get_sigframe_size()); \
} while (0)
#define AT_SYSINFO 32
@@ -12,9 +12,9 @@
/* entries in ARCH_DLINFO: */
#if defined(CONFIG_IA32_EMULATION) || !defined(CONFIG_X86_64)
-# define AT_VECTOR_SIZE_ARCH 2
+# define AT_VECTOR_SIZE_ARCH 3
#else /* else it's non-compat x86-64 */
-# define AT_VECTOR_SIZE_ARCH 1
+# define AT_VECTOR_SIZE_ARCH 2
#endif
#endif /* _ASM_X86_AUXVEC_H */
@@ -716,6 +716,11 @@ void __init init_sigframe_size(void)
max_frame_size = round_up(max_frame_size, FRAME_ALIGNMENT);
}
+unsigned long get_sigframe_size(void)
+{
+ return max_frame_size;
+}
+
static inline int is_ia32_compat_frame(struct ksignal *ksig)
{
return IS_ENABLED(CONFIG_IA32_EMULATION) &&
Historically, signal.h defines MINSIGSTKSZ (2KB) and SIGSTKSZ (8KB), for use by all architectures with sigaltstack(2). Over time, the hardware state size grew, but these constants did not evolve. Today, literal use of these constants on several architectures may result in signal stack overflow, and thus user data corruption. A few years ago, the ARM team addressed this issue by establishing getauxval(AT_MINSIGSTKSZ), such that the kernel can supply at runtime value that is an appropriate replacement on the current and future hardware. Add getauxval(AT_MINSIGSTKSZ) support to x86, analogous to the support added for ARM in commit 94b07c1f8c39 ("arm64: signal: Report signal frame size to userspace via auxv"). Reported-by: Florian Weimer <fweimer@redhat.com> Fixes: c2bc11f10a39 ("x86, AVX-512: Enable AVX-512 States Context Switch") Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> Reviewed-by: Len Brown <len.brown@intel.com> Cc: H.J. Lu <hjl.tools@gmail.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Dave Martin <Dave.Martin@arm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: x86@kernel.org Cc: libc-alpha@sourceware.org Cc: linux-arch@vger.kernel.org Cc: linux-api@vger.kernel.org Cc: linux-kernel@vger.kernel.org Link: https://bugzilla.kernel.org/show_bug.cgi?id=153531 --- arch/x86/include/asm/elf.h | 4 ++++ arch/x86/include/uapi/asm/auxvec.h | 4 ++-- arch/x86/kernel/signal.c | 5 +++++ 3 files changed, 11 insertions(+), 2 deletions(-)