https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121930
Bug ID: 121930
Summary: c/c++ front ends doesn't check __stack_chk_guard
conflict
Product: gcc
Version: 15.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: hjl.tools at gmail dot com
Target Milestone: ---
[hjl@gnu-cfl-3 pr121911]$ cat s.c
static int __stack_chk_guard;
int *
smash (char *p, int i)
{
p[i] = __stack_chk_guard;
return &__stack_chk_guard;
}
[hjl@gnu-cfl-3 pr121911]$ make CC=gcc s.s
gcc -fPIC -fstack-protector-all -mstack-protector-guard=global -S s.c
[hjl@gnu-cfl-3 pr121911]$ cat s.s
.file "s.c"
.text
.local __stack_chk_guard
.comm __stack_chk_guard,4,4
.globl smash
.type smash, @function
smash:
.LFB0:
.cfi_startproc
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset 6, -16
movq %rsp, %rbp
.cfi_def_cfa_register 6
subq $32, %rsp
movq %rdi, -24(%rbp)
movl %esi, -28(%rbp)
movq __stack_chk_guard@GOTPCREL(%rip), %rax
movq (%rax), %rsi
movq %rsi, -8(%rbp)
xorl %esi, %esi
movl __stack_chk_guard(%rip), %ecx
movl -28(%rbp), %eax
movslq %eax, %rdx
movq -24(%rbp), %rax
addq %rdx, %rax
movl %ecx, %edx
movb %dl, (%rax)
leaq __stack_chk_guard(%rip), %rax
^^^^^^^^^^^^ File scope variable.
movq %rax, %rdx
movq __stack_chk_guard@GOTPCREL(%rip), %rax
^^^^^^^^^^^^^^^^ Global variable.
movq -8(%rbp), %rdi
subq (%rax), %rdi
je .L3
call __stack_chk_fail@PLT
.L3:
movq %rdx, %rax
leave
.cfi_def_cfa 7, 8
ret
.cfi_endproc
.LFE0:
.size smash, .-smash
.ident "GCC: (GNU) 15.2.1 20250808 (Red Hat 15.2.1-1)"
.section .note.GNU-stack,"",@progbits
[hjl@gnu-cfl-3 pr121911]$
