From: Herbert Xu Date: Mon, 21 Apr 2025 03:31:31 +0000 (+0800) Subject: crypto: scomp - Fix off-by-one bug when calculating last page X-Git-Tag: v6.15-rc4~31^2~1 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=002ba346e3d76bb2b09448beed06c5ea1b0e06b8;p=thirdparty%2Flinux.git crypto: scomp - Fix off-by-one bug when calculating last page Fix off-by-one bug in the last page calculation for src and dst. Reported-by: Nhat Pham Fixes: 2d3553ecb4e3 ("crypto: scomp - Remove support for some non-trivial SG lists") Signed-off-by: Herbert Xu --- diff --git a/crypto/scompress.c b/crypto/scompress.c index 5762fcc63b515..36934c78d1277 100644 --- a/crypto/scompress.c +++ b/crypto/scompress.c @@ -215,8 +215,8 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir) spage = nth_page(spage, soff / PAGE_SIZE); soff = offset_in_page(soff); - n = slen / PAGE_SIZE; - n += (offset_in_page(slen) + soff - 1) / PAGE_SIZE; + n = (slen - 1) / PAGE_SIZE; + n += (offset_in_page(slen - 1) + soff) / PAGE_SIZE; if (PageHighMem(nth_page(spage, n)) && size_add(soff, slen) > PAGE_SIZE) break; @@ -243,9 +243,9 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir) dpage = nth_page(dpage, doff / PAGE_SIZE); doff = offset_in_page(doff); - n = dlen / PAGE_SIZE; - n += (offset_in_page(dlen) + doff - 1) / PAGE_SIZE; - if (PageHighMem(dpage + n) && + n = (dlen - 1) / PAGE_SIZE; + n += (offset_in_page(dlen - 1) + doff) / PAGE_SIZE; + if (PageHighMem(nth_page(dpage, n)) && size_add(doff, dlen) > PAGE_SIZE) break; dst = kmap_local_page(dpage) + doff;