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From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org,
	Wilco Dijkstra <Wilco.Dijkstra@arm.com>,
	Yu Chien Peter Lin <peterlin@andestech.com>
Subject: [PATCH v2] malloc: Do not clobber errno on __getrandom_nocancel (BZ#29624)
Date: Thu, 29 Sep 2022 14:55:26 -0300	[thread overview]
Message-ID: <20220929175526.2596756-1-adhemerval.zanella@linaro.org> (raw)

Use INTERNAL_SYSCALL_CALL instead of INLINE_SYSCALL_CALL.  This
requires emulate the semantic for hurd call (so __arc4random_buf
uses the fallback).

Checked on x86_64-linux-gnu.
---
 stdlib/arc4random.c                  |  4 ++--
 sysdeps/mach/hurd/not-cancel.h       | 12 ++++++++++--
 sysdeps/unix/sysv/linux/not-cancel.h |  2 +-
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/stdlib/arc4random.c b/stdlib/arc4random.c
index e417ef624d..0a1f4b8a57 100644
--- a/stdlib/arc4random.c
+++ b/stdlib/arc4random.c
@@ -34,7 +34,7 @@ void
 __arc4random_buf (void *p, size_t n)
 {
   static int seen_initialized;
-  size_t l;
+  int l;
   int fd;
 
   if (n == 0)
@@ -51,7 +51,7 @@ __arc4random_buf (void *p, size_t n)
 	  n -= l;
 	  continue; /* Interrupted by a signal; keep going.  */
 	}
-      else if (l < 0 && errno == ENOSYS)
+      else if (l == -ENOSYS)
 	break; /* No syscall, so fallback to /dev/urandom.  */
       arc4random_getrandom_failure ();
     }
diff --git a/sysdeps/mach/hurd/not-cancel.h b/sysdeps/mach/hurd/not-cancel.h
index ae58b734e3..518f738519 100644
--- a/sysdeps/mach/hurd/not-cancel.h
+++ b/sysdeps/mach/hurd/not-cancel.h
@@ -27,6 +27,7 @@
 #include <sys/uio.h>
 #include <hurd.h>
 #include <hurd/fd.h>
+#include <sys/random.h>
 
 /* Non cancellable close syscall.  */
 __typeof (__close) __close_nocancel;
@@ -75,8 +76,15 @@ __typeof (__fcntl) __fcntl_nocancel;
 #define __fcntl64_nocancel(...) \
   __fcntl_nocancel (__VA_ARGS__)
 
-#define __getrandom_nocancel(buf, size, flags) \
-  __getrandom (buf, size, flags)
+static inline int
+__getrandom_nocancel (void *buf, size_t buflen, unsigned int flags)
+{
+  int save_errno = errno;
+  int r = __getrandom (buf, buflen, flags);
+  r = r == -1 ? -errno : r;
+  __set_errno (save_errno);
+  return r;
+}
 
 #define __poll_infinity_nocancel(fds, nfds) \
   __poll (fds, nfds, -1)
diff --git a/sysdeps/unix/sysv/linux/not-cancel.h b/sysdeps/unix/sysv/linux/not-cancel.h
index a263d294b1..00ab75a405 100644
--- a/sysdeps/unix/sysv/linux/not-cancel.h
+++ b/sysdeps/unix/sysv/linux/not-cancel.h
@@ -71,7 +71,7 @@ __writev_nocancel_nostatus (int fd, const struct iovec *iov, int iovcnt)
 static inline int
 __getrandom_nocancel (void *buf, size_t buflen, unsigned int flags)
 {
-  return INLINE_SYSCALL_CALL (getrandom, buf, buflen, flags);
+  return INTERNAL_SYSCALL_CALL (getrandom, buf, buflen, flags);
 }
 
 static inline int
-- 
2.34.1


             reply	other threads:[~2022-09-29 17:55 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-29 17:55 Adhemerval Zanella [this message]
2022-09-29 18:36 ` Wilco Dijkstra
2022-09-29 19:07   ` Adhemerval Zanella Netto
2022-09-29 19:36     ` H.J. Lu
2022-09-29 18:44 ` Yann Droneaud

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