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authorSzabolcs Nagy <szabolcs.nagy@arm.com>2022-07-15 14:10:53 +0100
committerSzabolcs Nagy <szabolcs.nagy@arm.com>2022-11-22 14:31:25 +0000
commit868b753880f56e598c62c5345769064d35cf9687 (patch)
tree12da8f98909e7ba3025a93713e01169ff81e169a /sysdeps
parent04d2fec011b657210a410e95ec61783f77987648 (diff)
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aarch64: morello: fix missing variadic argument in fcntl
In fcntl va_arg is currently used even if the caller did not pass
any variadic arguments. This is undefined behaviour and does not
work with the Morello purecap ABI, so use a helper macro.

When the argument is missing, the result of the helper macro is
arbitrary as it will be ignored by the kernel, we just have to
ensure it does not cause a runtime crash.
Diffstat (limited to 'sysdeps')
-rw-r--r--sysdeps/unix/sysv/linux/aarch64/morello/sysdep.h2
-rw-r--r--sysdeps/unix/sysv/linux/fcntl64.c6
-rw-r--r--sysdeps/unix/sysv/linux/fcntl_nocancel.c6
3 files changed, 12 insertions, 2 deletions
diff --git a/sysdeps/unix/sysv/linux/aarch64/morello/sysdep.h b/sysdeps/unix/sysv/linux/aarch64/morello/sysdep.h
index 5db89b096d..bad64a0674 100644
--- a/sysdeps/unix/sysv/linux/aarch64/morello/sysdep.h
+++ b/sysdeps/unix/sysv/linux/aarch64/morello/sysdep.h
@@ -105,6 +105,8 @@ typedef __intcap_t __sysarg_t;
   LOAD_ARGS_6 (c0, c1, c2, c3, c4, c5)		\
   register __sysarg_t _x6 asm ("c6") = _x6tmp;
 
+# define FCNTL_VA_ARG(a, t) (a ? va_arg(a, t) : 0)
+
 #endif	/* __ASSEMBLER__ */
 
 /* Disable pointer mangling for purecap ABI.  */
diff --git a/sysdeps/unix/sysv/linux/fcntl64.c b/sysdeps/unix/sysv/linux/fcntl64.c
index 5192b2d672..0b6afd3b59 100644
--- a/sysdeps/unix/sysv/linux/fcntl64.c
+++ b/sysdeps/unix/sysv/linux/fcntl64.c
@@ -29,6 +29,10 @@
 # define __NR_fcntl64 __NR_fcntl
 #endif
 
+#ifndef FCNTL_VA_ARG
+# define FCNTL_VA_ARG(a, t) va_arg(a, t)
+#endif
+
 #ifndef FCNTL_ADJUST_CMD
 # define FCNTL_ADJUST_CMD(__cmd) __cmd
 #endif
@@ -40,7 +44,7 @@ __libc_fcntl64 (int fd, int cmd, ...)
   void *arg;
 
   va_start (ap, cmd);
-  arg = va_arg (ap, void *);
+  arg = FCNTL_VA_ARG (ap, void *);
   va_end (ap);
 
   cmd = FCNTL_ADJUST_CMD (cmd);
diff --git a/sysdeps/unix/sysv/linux/fcntl_nocancel.c b/sysdeps/unix/sysv/linux/fcntl_nocancel.c
index 7c38e22399..f21b56d95b 100644
--- a/sysdeps/unix/sysv/linux/fcntl_nocancel.c
+++ b/sysdeps/unix/sysv/linux/fcntl_nocancel.c
@@ -26,6 +26,10 @@
 # define __NR_fcntl64 __NR_fcntl
 #endif
 
+#ifndef FCNTL_VA_ARG
+# define FCNTL_VA_ARG(a, t) va_arg(a, t)
+#endif
+
 #ifndef FCNTL_ADJUST_CMD
 # define FCNTL_ADJUST_CMD(__cmd) __cmd
 #endif
@@ -37,7 +41,7 @@ __fcntl64_nocancel (int fd, int cmd, ...)
   void *arg;
 
   va_start (ap, cmd);
-  arg = va_arg (ap, void *);
+  arg = FCNTL_VA_ARG (ap, void *);
   va_end (ap);
 
   cmd = FCNTL_ADJUST_CMD (cmd);