[dm-devel] [PATCH v2 2/4] libmpathpersist: format_transportids(): avoid PROUT overflow
Benjamin Marzinski
bmarzins at redhat.com
Tue Mar 17 19:28:39 UTC 2020
On Sun, Mar 15, 2020 at 10:05:19PM +0100, mwilck at suse.com wrote:
> From: Martin Wilck <mwilck at suse.com>
>
> This limits the PERSISTENT RESERVE OUT data size to max. 8192 bytes.
>
Reviewed-by: Benjamin Marzinski <bmarzins at redhat.com>
> 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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