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authorJ. Bruce Fields <bfields@redhat.com>2016-03-01 04:21:21 +0300
committerJ. Bruce Fields <bfields@redhat.com>2016-03-02 00:02:57 +0300
commit4aed9c46afb80164401143aa0fdcfe3798baa9d5 (patch)
treefa0cae60a7a74660937630b60e4c255774777a85
parentb7052cd7bcf3c1478796e93e3dff2b44c9e82943 (diff)
downloadlinux-4aed9c46afb80164401143aa0fdcfe3798baa9d5.tar.xz
nfsd4: fix bad bounds checking
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. Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com>
-rw-r--r--fs/nfsd/nfs4xdr.c13
1 files changed, 8 insertions, 5 deletions
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index d6ef0955a979..1600ec470ce7 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1072,8 +1072,9 @@ nfsd4_decode_rename(struct nfsd4_compoundargs *argp, struct nfsd4_rename *rename
READ_BUF(4);
rename->rn_snamelen = be32_to_cpup(p++);
- READ_BUF(rename->rn_snamelen + 4);
+ READ_BUF(rename->rn_snamelen);
SAVEMEM(rename->rn_sname, rename->rn_snamelen);
+ READ_BUF(4);
rename->rn_tnamelen = be32_to_cpup(p++);
READ_BUF(rename->rn_tnamelen);
SAVEMEM(rename->rn_tname, rename->rn_tnamelen);
@@ -1155,13 +1156,14 @@ nfsd4_decode_setclientid(struct nfsd4_compoundargs *argp, struct nfsd4_setclient
READ_BUF(8);
setclientid->se_callback_prog = be32_to_cpup(p++);
setclientid->se_callback_netid_len = be32_to_cpup(p++);
-
- 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);
setclientid->se_callback_addr_len = be32_to_cpup(p++);
- 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);
setclientid->se_callback_ident = be32_to_cpup(p++);
DECODE_TAIL;
@@ -1835,8 +1837,9 @@ nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
READ_BUF(4);
argp->taglen = be32_to_cpup(p++);
- READ_BUF(argp->taglen + 8);
+ READ_BUF(argp->taglen);
SAVEMEM(argp->tag, argp->taglen);
+ READ_BUF(8);
argp->minorversion = be32_to_cpup(p++);
argp->opcnt = be32_to_cpup(p++);
max_reply += 4 + (XDR_QUADLEN(argp->taglen) << 2);