linux-user: Fix setreuid and setregid to use direct syscalls

Commit Message

Helge Deller Nov. 5, 2024, 3:15 p.m. UTC

The commit fd6f7798ac30 ("linux-user: Use direct syscalls for setuid(),
etc") added direct syscall wrappers for setuid(), setgid(), etc since the
system calls have different semantics than the libc functions.

Add and use the corresponding wrappers for setreuid and setregid which
were missed in that commit.

This fixes the build of the debian package of the uid_wrapper library
(https://cwrap.org/uid_wrapper.html) when running linux-user.

Signed-off-by: Helge Deller <[e-mail]>

Comments

Ilya Leoshkevich Nov. 5, 2024, 3:59 p.m. UTC | #1

On Tue, 2024-11-05 at 16:15 +0100, Helge Deller wrote:
> The commit fd6f7798ac30 ("linux-user: Use direct syscalls for
> setuid(),
> etc") added direct syscall wrappers for setuid(), setgid(), etc since
> the
> system calls have different semantics than the libc functions.
> 
> Add and use the corresponding wrappers for setreuid and setregid
> which
> were missed in that commit.
> 
> This fixes the build of the debian package of the uid_wrapper library
> (https://cwrap.org/uid_wrapper.html) when running linux-user.
> 
> Signed-off-by: Helge Deller <[e-mail]>

Reviewed-by: Ilya Leoshkevich <[e-mail]>

I should've checked the other syscalls when fixing setgroups recently.
Seems like with this patch, linux-user will no longer call glibc
functions that use INLINE_SETXID_SYSCALL().

Patch

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 59b2080b98..0279f23576 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -7233,12 +7233,24 @@  static inline int tswapid(int id)
 #else
 #define __NR_sys_setgroups __NR_setgroups
 #endif
+#ifdef __NR_sys_setreuid32
+#define __NR_sys_setreuid __NR_setreuid32
+#else
+#define __NR_sys_setreuid __NR_setreuid
+#endif
+#ifdef __NR_sys_setregid32
+#define __NR_sys_setregid __NR_setregid32
+#else
+#define __NR_sys_setregid __NR_setregid
+#endif
 
 _syscall1(int, sys_setuid, uid_t, uid)
 _syscall1(int, sys_setgid, gid_t, gid)
 _syscall3(int, sys_setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
 _syscall3(int, sys_setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
 _syscall2(int, sys_setgroups, int, size, gid_t *, grouplist)
+_syscall2(int, sys_setreuid, uid_t, ruid, uid_t, euid);
+_syscall2(int, sys_setregid, gid_t, rgid, gid_t, egid);
 
 void syscall_init(void)
 {
@@ -11932,9 +11944,9 @@  static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1,
         return get_errno(high2lowgid(getegid()));
 #endif
     case TARGET_NR_setreuid:
-        return get_errno(setreuid(low2highuid(arg1), low2highuid(arg2)));
+        return get_errno(sys_setreuid(low2highuid(arg1), low2highuid(arg2)));
     case TARGET_NR_setregid:
-        return get_errno(setregid(low2highgid(arg1), low2highgid(arg2)));
+        return get_errno(sys_setregid(low2highgid(arg1), low2highgid(arg2)));
     case TARGET_NR_getgroups:
         { /* the same code as for TARGET_NR_getgroups32 */
             int gidsetsize = arg1;
@@ -12264,11 +12276,11 @@  static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1,
 #endif
 #ifdef TARGET_NR_setreuid32
     case TARGET_NR_setreuid32:
-        return get_errno(setreuid(arg1, arg2));
+        return get_errno(sys_setreuid(arg1, arg2));
 #endif
 #ifdef TARGET_NR_setregid32
     case TARGET_NR_setregid32:
-        return get_errno(setregid(arg1, arg2));
+        return get_errno(sys_setregid(arg1, arg2));
 #endif
 #ifdef TARGET_NR_getgroups32
     case TARGET_NR_getgroups32: