From: J. Bruce Fields Date: Tue, 1 Mar 2016 01:21:21 +0000 (-0500) Subject: nfsd4: fix bad bounds checking X-Git-Tag: v3.2.80~98 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=49c27d2f5606239806bb4527c2fd19d488094fb6;p=pandora-kernel.git nfsd4: fix bad bounds checking commit 4aed9c46afb80164401143aa0fdcfe3798baa9d5 upstream. A number of spots in the xdr decoding follow a pattern like n = be32_to_cpup(p++); READ_BUF(n + 4); where n is a u32. The only bounds checking is done in READ_BUF itself, but since it's checking (n + 4), it won't catch cases where n is very large, (u32)(-4) or higher. I'm not sure exactly what the consequences are, but we've seen crashes soon after. Instead, just break these up into two READ_BUF()s. Signed-off-by: J. Bruce Fields [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index 9d2c52b03bd2..31352e2bec29 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -931,8 +931,9 @@ nfsd4_decode_rename(struct nfsd4_compoundargs *argp, struct nfsd4_rename *rename READ_BUF(4); READ32(rename->rn_snamelen); - READ_BUF(rename->rn_snamelen + 4); + READ_BUF(rename->rn_snamelen); SAVEMEM(rename->rn_sname, rename->rn_snamelen); + READ_BUF(4); READ32(rename->rn_tnamelen); READ_BUF(rename->rn_tnamelen); SAVEMEM(rename->rn_tname, rename->rn_tnamelen); @@ -1009,13 +1010,14 @@ nfsd4_decode_setclientid(struct nfsd4_compoundargs *argp, struct nfsd4_setclient READ_BUF(8); READ32(setclientid->se_callback_prog); READ32(setclientid->se_callback_netid_len); - - READ_BUF(setclientid->se_callback_netid_len + 4); + READ_BUF(setclientid->se_callback_netid_len); SAVEMEM(setclientid->se_callback_netid_val, setclientid->se_callback_netid_len); + READ_BUF(4); READ32(setclientid->se_callback_addr_len); - READ_BUF(setclientid->se_callback_addr_len + 4); + READ_BUF(setclientid->se_callback_addr_len); SAVEMEM(setclientid->se_callback_addr_val, setclientid->se_callback_addr_len); + READ_BUF(4); READ32(setclientid->se_callback_ident); DECODE_TAIL; @@ -1584,8 +1586,9 @@ nfsd4_decode_compound(struct nfsd4_compoundargs *argp) */ READ_BUF(4); READ32(argp->taglen); - READ_BUF(argp->taglen + 8); + READ_BUF(argp->taglen); SAVEMEM(argp->tag, argp->taglen); + READ_BUF(8); READ32(argp->minorversion); READ32(argp->opcnt);