HAProxy will crash with the following configuration:
global
...
tune.bufsize 1024
tune.maxrewrite 0
frontend xxx
...
backend yyy
...
cookie cookie insert maxidle 300s
If client sends a request of which object size is more than tune.bufsize (1024
bytes), HAProxy will crash.
After doing some debugging, the crash was caused by http_header_add_tail2() ->
buffer_insert_line2() while inserting cookie at the end of response header.
Part codes of buffer_insert_line2() are as below:
int buffer_insert_line2(struct buffer *b, char *pos, const char *str, int len)
{
int delta;
delta = len + 2;
if (bi_end(b) + delta >= b->data + b->size)
return 0; /* no space left */
/* first, protect the end of the buffer */
memmove(pos + delta, pos, bi_end(b) - pos);
...
}
Since tune.maxrewrite is 0, HAProxy can receive 1024 bytes once which is equals
to full buffer size. Under such condition, the buffer is full and bi_end(b)
will be wrapped to the start of buffer which pointed to b->data. As a result,
though there is no space left in buffer, the check condition
if (bi_end(b) + delta >= b->data + b->size)
will be true, then memmove() is called, and (pos + delta) will exceed the end
of buffer (b->data + b->size), HAProxy crashes
Just take buffer_replace2() as a reference, the other check when input data in
a buffer is wrapped should be also added into buffer_insert_line2().
This fix must be backported to 1.5.
Signed-off-by: Godbach <nylzhaowei@gmail.com>
Commit c08057c does the align job for buffer_dump(), but it has not fixed the
issue that less than 8 characters are left in the last line as below:
Dumping contents from byte 0 to byte 119
0 1 2 3 4 5 6 7 8 9 a b c d e f
0000: 47 45 54 20 2f 69 6e 64 - 65 78 2e 68 74 6d 20 48 GET /index.htm H
0010: 54 54 50 2f 31 2e 30 0d - 0a 55 73 65 72 2d 41 67 TTP/1.0..User-Ag
...
0060: 6e 65 63 74 69 6f 6e 3a - 20 4b 65 65 70 2d 41 6c nection: Keep-Al
0070: 69 76 65 0d 0a 0d 0a ive....
The last line of the hex column is still overlapped by the text column. Since
there will be additional "- " for the output line which has no less than 8
characters, two additional spaces should be present when there is less than 8
characters in order to do alignment. The result after being fixed is as below:
Dumping contents from byte 0 to byte 119
0 1 2 3 4 5 6 7 8 9 a b c d e f
0000: 47 45 54 20 2f 69 6e 64 - 65 78 2e 68 74 6d 20 48 GET /index.htm H
0010: 54 54 50 2f 31 2e 30 0d - 0a 55 73 65 72 2d 41 67 TTP/1.0..User-Ag
...
0060: 6e 65 63 74 69 6f 6e 3a - 20 4b 65 65 70 2d 41 6c nection: Keep-Al
0070: 69 76 65 0d 0a 0d 0a ive....
Signed-off-by: Godbach <nylzhaowei@gmail.com>
If the dumped length of buffer is not multiple of 16, the last output line can
be seen as below:
Dumping contents from byte 0 to byte 125
0 1 2 3 4 5 6 7 8 9 a b c d e f
0000: 47 45 54 20 2f 69 6e 64 - 65 78 2e 68 74 6d 20 48 GET /index.htm H
0010: 54 54 50 2f 31 2e 30 0d - 0a 55 73 65 72 2d 41 67 TTP/1.0..User-Ag
...
0060: 30 0d 0a 43 6f 6e 6e 65 - 63 74 69 6f 6e 3a 20 4b 0..Connection: K
0070: 65 65 70 2d 41 6c 69 76 - 65 0d 0a 0d 0a eep-Alive....
Yes, the hex column will be overlapped by the text column. Both the hex and
text column should be aligned at their own area as below:
Dumping contents from byte 0 to byte 125
0 1 2 3 4 5 6 7 8 9 a b c d e f
0000: 47 45 54 20 2f 69 6e 64 - 65 78 2e 68 74 6d 20 48 GET /index.htm H
0010: 54 54 50 2f 31 2e 30 0d - 0a 55 73 65 72 2d 41 67 TTP/1.0..User-Ag
...
0060: 30 0d 0a 43 6f 6e 6e 65 - 63 74 69 6f 6e 3a 20 4b 0..Connection: K
0070: 65 65 70 2d 41 6c 69 76 - 65 0d 0a 0d 0a eep-Alive....
Signed-off-by: Godbach <nylzhaowei@gmail.com>
With this commit, we now separate the channel from the buffer. This will
allow us to replace buffers on the fly without touching the channel. Since
nobody is supposed to keep a reference to a buffer anymore, doing so is not
a problem and will also permit some copy-less data manipulation.
Interestingly, these changes have shown a 2% performance increase on some
workloads, probably due to a better cache placement of data.
These functions do not depend on the channel flags anymore thus they're
much better suited to be used on plain buffers. Move them from channel
to buffer.
