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Fix a stack overflow in mount_smbfs when hostname is too long.

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The local hostname was blindly copied into the to the nn_name array.
When the hostname exceeded 16 bytes, it would overflow.  Truncate the
hostname to 15 bytes plus a 0 terminator which is the "workstation name"
suffix.

Use defensive strlcpy() when filling nn_name in all cases.

PR:		228354
Reported by:	donald.buchholz@intel.com
Reviewed by:	jpaetzel,  ian (prior version)
Discussed with:	Security Officer (gtetlow)
MFC after:	3 days
Security:	Stack overflow with the hostname.
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D15936
This commit is contained in:
Brooks Davis 2018-06-25 16:42:49 +00:00
parent 3911ee2c92
commit ccbbd187b1
2 changed files with 9 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
contrib/smbfs/lib/smb/ctx.c
View File

@ -549,7 +549,9 @@ smb_ctx_resolve(struct smb_ctx *ctx)
}
nn.nn_scope = ctx->ct_nb->nb_scope;
nn.nn_type = NBT_SERVER;
strcpy(nn.nn_name, ssn->ioc_srvname);
if (strlen(ssn->ioc_srvname) > NB_NAMELEN)
return NBERROR(NBERR_NAMETOOLONG);
strlcpy(nn.nn_name, ssn->ioc_srvname, sizeof(nn.nn_name));
error = nb_sockaddr(sap, &nn, &saserver);
nb_snbfree(sap);
if (error) {
@ -565,7 +567,11 @@ smb_ctx_resolve(struct smb_ctx *ctx)
}
nls_str_upper(ctx->ct_locname, ctx->ct_locname);
}
strcpy(nn.nn_name, ctx->ct_locname);
/*
* Truncate the local host name to NB_NAMELEN-1 which gives a
* suffix of 0 which is "workstation name".
*/
strlcpy(nn.nn_name, ctx->ct_locname, NB_NAMELEN);
nn.nn_type = NBT_WKSTA;
nn.nn_scope = ctx->ct_nb->nb_scope;
error = nb_sockaddr(NULL, &nn, &salocal);

2
contrib/smbfs/lib/smb/nbns_rq.c
View File

@ -74,7 +74,7 @@ nbns_resolvename(const char *name, struct nb_ctx *ctx, struct sockaddr **adpp)
if (error)
return error;
bzero(&nn, sizeof(nn));
strcpy(nn.nn_name, name);
strlcpy(nn.nn_name, name, sizeof(nn.nn_name));
nn.nn_scope = ctx->nb_scope;
nn.nn_type = NBT_SERVER;
rqp->nr_nmflags = NBNS_NMFLAG_RD;