[prev in list] [next in list] [prev in thread] [next in thread] 

List:       libguestfs
Subject:    [Libguestfs] [PATCH 2/2] SSH: Don't mix buffered reads with sysread
From:       Matthew Booth <mbooth () redhat ! com>
Date:       2010-04-29 10:47:49
Message-ID: 1272538069-16457-2-git-send-email-mbooth () redhat ! com
[Download RAW message or body]

SSH transfer contained a race due to use of buffered IO to read the initial
size, followed by sysread() to read the data. If data was available for reading
at the time the size was read, some of it would be consumed and buffered. It
would subsequently not be available to sysread(), meaning it wasn't copied.

Fix by using buffered IO consistently.
---
 lib/Sys/VirtV2V/Transfer/SSH.pm |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/lib/Sys/VirtV2V/Transfer/SSH.pm b/lib/Sys/VirtV2V/Transfer/SSH.pm
index ac5a384..0868b37 100644
--- a/lib/Sys/VirtV2V/Transfer/SSH.pm
+++ b/lib/Sys/VirtV2V/Transfer/SSH.pm
@@ -86,7 +86,7 @@ sub transfer
     for (;;) {
         my $buffer;
         # Transfer in 8k chunks
-        my $in = sysread($fh, $buffer, 8 * 1024);
+        my $in = read($fh, $buffer, 8 * 1024);
         die(user_message(__x("Error reading data from {path}: {error}",
                              path => $path,
                              error => $!))) if (!defined($in));
-- 
1.6.6.1

[prev in list] [next in list] [prev in thread] [next in thread]