[dm-devel] [PATCH v2 2/4] libmpathpersist: format_transportids(): avoid PROUT overflow
mwilck at suse.com
mwilck at suse.com
Sun Mar 15 21:05:19 UTC 2020
From: Martin Wilck <mwilck at suse.com>
This limits the PERSISTENT RESERVE OUT data size to max. 8192 bytes.
Signed-off-by: Martin Wilck <mwilck at suse.com>
---
libmpathpersist/mpath_pr_ioctl.c | 31 +++++++++++++++++++++++++++++--
1 file changed, 29 insertions(+), 2 deletions(-)
diff --git a/libmpathpersist/mpath_pr_ioctl.c b/libmpathpersist/mpath_pr_ioctl.c
index 1a28cba7..c78e8000 100644
--- a/libmpathpersist/mpath_pr_ioctl.c
+++ b/libmpathpersist/mpath_pr_ioctl.c
@@ -1,5 +1,6 @@
#include <stdio.h>
#include <stdlib.h>
+#include <stddef.h>
#include <sys/types.h>
#include <sys/stat.h>
@@ -138,38 +139,64 @@ retry :
return status;
}
+/*
+ * Helper macro to avoid overflow of prout_param_descriptor in
+ * format_transportids(). Data must not be written past
+ * MPATH_MAX_PARAM_LEN bytes from struct prout_param_descriptor.
+ */
+#define check_overflow(ofs, n, start, label) \
+ do { \
+ if ((ofs) + (n) + \
+ offsetof(struct prout_param_descriptor, private_buffer) \
+ > MPATH_MAX_PARAM_LEN) \
+ { \
+ (ofs) = (start); \
+ goto label; \
+ } \
+ } while(0)
+
uint32_t format_transportids(struct prout_param_descriptor *paramp)
{
unsigned int i = 0, len;
uint32_t buff_offset = 4;
- memset(paramp->private_buffer, 0, MPATH_MAX_PARAM_LEN);
+ memset(paramp->private_buffer, 0, sizeof(paramp->private_buffer));
for (i=0; i < paramp->num_transportid; i++ )
{
+ uint32_t start_offset = buff_offset;
+
+ check_overflow(buff_offset, 1, start_offset, end_loop);
paramp->private_buffer[buff_offset] = (uint8_t)((paramp->trnptid_list[i]->format_code & 0xff)|
(paramp->trnptid_list[i]->protocol_id & 0xff));
buff_offset += 1;
switch(paramp->trnptid_list[i]->protocol_id)
{
case MPATH_PROTOCOL_ID_FC:
+ check_overflow(buff_offset, 7 + 8 + 8,
+ start_offset, end_loop);
buff_offset += 7;
memcpy(¶mp->private_buffer[buff_offset], ¶mp->trnptid_list[i]->n_port_name, 8);
buff_offset +=8 ;
buff_offset +=8 ;
break;
case MPATH_PROTOCOL_ID_SAS:
+ check_overflow(buff_offset, 3 + 12,
+ start_offset, end_loop);
buff_offset += 3;
memcpy(¶mp->private_buffer[buff_offset], ¶mp->trnptid_list[i]->sas_address, 8);
buff_offset += 12;
break;
case MPATH_PROTOCOL_ID_ISCSI:
- buff_offset += 1;
len = (paramp->trnptid_list[i]->iscsi_name[1] & 0xff)+2;
+ check_overflow(buff_offset, 1 + len,
+ start_offset, end_loop);
+ buff_offset += 1;
memcpy(¶mp->private_buffer[buff_offset], ¶mp->trnptid_list[i]->iscsi_name,len);
buff_offset += len ;
break;
}
}
+end_loop:
buff_offset -= 4;
paramp->private_buffer[0] = (unsigned char)((buff_offset >> 24) & 0xff);
paramp->private_buffer[1] = (unsigned char)((buff_offset >> 16) & 0xff);
--
2.25.1
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