linux-kernel - [PATCH] coredump: Retry writes where appropriate

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 31 May 2009 01:33:39 -0400
From:	Paul Smith <paul@...-scientist.net>
To:	linux-kernel@...r.kernel.org
Cc:	stable@...nel.org, Andrew Morton <akpm@...ux-foundation.org>,
	Andi Kleen <andi@...stfloor.org>,
	Oleg Nesterov <oleg@...hat.com>,
	Roland McGrath <roland@...hat.com>
Subject: [PATCH] coredump: Retry writes where appropriate

coredump: Retry writes where appropriate

Core dump write operations (especially to a pipe) can be incomplete due
to signal reception or possibly recoverable partial writes.

Previously any incomplete write in the ELF core dumper caused the core
dump to stop, giving short cores in these cases.  Modify the core dumper
to retry the write where appropriate.

Signed-off-by: Paul Smith <paul@...-scientist.net>
Cc: stable@...nel.org

---

 fs/binfmt_elf.c |   19 ++++++++++++++++++-
 1 files changed, 18 insertions(+), 1 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 40381df..26b03cc 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1119,7 +1119,24 @@ out:
  */
 static int dump_write(struct file *file, const void *addr, int nr)
 {
-	return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
+	const char *p = addr;
+	while (1) {
+		int r = file->f_op->write(file, p, nr, &file->f_pos);
+
+		if (likely(r == nr))
+			return 1;
+
+		if (r == -ERESTARTSYS || r == -EAGAIN || r == -EINTR)
+			/* Ignore signals during coredump. */
+			clear_thread_flag(TIF_SIGPENDING);
+		else if (r > 0) {
+			/* Partial write: try again with the rest. */
+			p += r;
+			nr -= r;
+		} else
+			/* Lose! */
+			return 0;
+	}
 }
 
 static int dump_seek(struct file *file, loff_t off)

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/