Commit fe4bfff8 authored by Kees Cook's avatar Kees Cook

seccomp: Use -1 marker for end of mode 1 syscall list

The terminator for the mode 1 syscalls list was a 0, but that could be
a valid syscall number (e.g. x86_64 __NR_read). By luck, __NR_read was
listed first and the loop construct would not test it, so there was no
bug. However, this is fragile. Replace the terminator with -1 instead,
and make the variable name for mode 1 syscall lists more descriptive.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will Drewry <wad@chromium.org>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent 47e33c05
......@@ -9,12 +9,12 @@ static inline const int *get_compat_mode1_syscalls(void)
static const int syscalls_O32[] = {
__NR_O32_Linux + 3, __NR_O32_Linux + 4,
__NR_O32_Linux + 1, __NR_O32_Linux + 193,
0, /* null terminated */
-1, /* negative terminated */
};
static const int syscalls_N32[] = {
__NR_N32_Linux + 0, __NR_N32_Linux + 1,
__NR_N32_Linux + 58, __NR_N32_Linux + 211,
0, /* null terminated */
-1, /* negative terminated */
};
if (IS_ENABLED(CONFIG_MIPS32_O32) && test_thread_flag(TIF_32BIT_REGS))
......
......@@ -33,7 +33,7 @@ static inline const int *get_compat_mode1_syscalls(void)
static const int mode1_syscalls_32[] = {
__NR_seccomp_read_32, __NR_seccomp_write_32,
__NR_seccomp_exit_32, __NR_seccomp_sigreturn_32,
0, /* null terminated */
-1, /* negative terminated */
};
return mode1_syscalls_32;
}
......
......@@ -742,20 +742,20 @@ static inline void seccomp_log(unsigned long syscall, long signr, u32 action,
*/
static const int mode1_syscalls[] = {
__NR_seccomp_read, __NR_seccomp_write, __NR_seccomp_exit, __NR_seccomp_sigreturn,
0, /* null terminated */
-1, /* negative terminated */
};
static void __secure_computing_strict(int this_syscall)
{
const int *syscall_whitelist = mode1_syscalls;
const int *allowed_syscalls = mode1_syscalls;
#ifdef CONFIG_COMPAT
if (in_compat_syscall())
syscall_whitelist = get_compat_mode1_syscalls();
allowed_syscalls = get_compat_mode1_syscalls();
#endif
do {
if (*syscall_whitelist == this_syscall)
if (*allowed_syscalls == this_syscall)
return;
} while (*++syscall_whitelist);
} while (*++allowed_syscalls != -1);
#ifdef SECCOMP_DEBUG
dump_stack();
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment