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Use size_add() and struct_size() to avoid integer overflows. Saving size_add()/struct_size() results to a u32 is unsafe because it truncates away the high bits. Also generally storing sizes in longs is safer. Most systems these days use 64 bit CPUs. It's harder for an addition to overflow 64 bits than it is to overflow 32 bits. Also functions like vmalloc() can successfully allocate UINT_MAX bytes, but nothing can allocate ULONG_MAX bytes. Signed-off-by: Dan Carpenter --- I think my patch 1 fixes any real issues. It's hard to assign a Fixes tag to this. fs/nfsd/nfs4xdr.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index c7bfd2180e3f..42b41d55d4ed 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -118,11 +118,11 @@ static int zero_clientid(clientid_t *clid) * operation described in @argp finishes. */ static void * -svcxdr_tmpalloc(struct nfsd4_compoundargs *argp, u32 len) +svcxdr_tmpalloc(struct nfsd4_compoundargs *argp, size_t len) { struct svcxdr_tmpbuf *tb; =20 - tb =3D kmalloc(sizeof(*tb) + len, GFP_KERNEL); + tb =3D kmalloc(struct_size(tb, buf, len), GFP_KERNEL); if (!tb) return NULL; tb->next =3D argp->to_free; @@ -138,9 +138,9 @@ svcxdr_tmpalloc(struct nfsd4_compoundargs *argp, u32 le= n) * buffer might end on a page boundary. */ static char * -svcxdr_dupstr(struct nfsd4_compoundargs *argp, void *buf, u32 len) +svcxdr_dupstr(struct nfsd4_compoundargs *argp, void *buf, size_t len) { - char *p =3D svcxdr_tmpalloc(argp, len + 1); + char *p =3D svcxdr_tmpalloc(argp, size_add(len, 1)); =20 if (!p) return NULL; @@ -150,7 +150,7 @@ svcxdr_dupstr(struct nfsd4_compoundargs *argp, void *bu= f, u32 len) } =20 static void * -svcxdr_savemem(struct nfsd4_compoundargs *argp, __be32 *p, u32 len) +svcxdr_savemem(struct nfsd4_compoundargs *argp, __be32 *p, size_t len) { __be32 *tmp; =20 @@ -2146,7 +2146,7 @@ nfsd4_decode_clone(struct nfsd4_compoundargs *argp, u= nion nfsd4_op_u *u) */ static __be32 nfsd4_vbuf_from_vector(struct nfsd4_compoundargs *argp, struct xdr_buf *xd= r, - char **bufp, u32 buflen) + char **bufp, size_t buflen) { struct page **pages =3D xdr->pages; struct kvec *head =3D xdr->head; --=20 2.43.0