From 4e73a15a7b64c409f91e1660d283965c2a3a3fd2 Mon Sep 17 00:00:00 2001 From: Thomas Perale Date: Tue, 2 Jun 2026 22:24:43 +0200 Subject: [PATCH] package/unzip: patch CVE-2021-4217 The patch is provided thanks to the Ubuntu community. - CVE-2021-4217: A flaw was found in unzip. The vulnerability occurs due to improper handling of Unicode strings, which can lead to a null pointer dereference. This flaw allows an attacker to input a specially crafted zip file, leading to a crash or code execution. For more information, see: - https://www.cve.org/CVERecord?id=CVE-2021-4217 - https://launchpadlibrarian.net/580782282/0001-Fix-null-pointer-dereference-and-use-of-uninitialized-data.patch - https://bugs.launchpad.net/ubuntu/+source/unzip/+bug/1957077 Signed-off-by: Thomas Perale [Peter: correct _IGNORE_CVES entry] Signed-off-by: Peter Korsgaard --- ...erence-and-use-of-uninitialized-data.patch | 57 +++++++++++++++++++ package/unzip/unzip.mk | 3 + 2 files changed, 60 insertions(+) create mode 100644 package/unzip/0032-Fix-null-pointer-dereference-and-use-of-uninitialized-data.patch diff --git a/package/unzip/0032-Fix-null-pointer-dereference-and-use-of-uninitialized-data.patch b/package/unzip/0032-Fix-null-pointer-dereference-and-use-of-uninitialized-data.patch new file mode 100644 index 0000000000..4f9c4c1858 --- /dev/null +++ b/package/unzip/0032-Fix-null-pointer-dereference-and-use-of-uninitialized-data.patch @@ -0,0 +1,57 @@ +From 731d698377dbd1f5b1b90efeb8094602ed59fc40 Mon Sep 17 00:00:00 2001 +From: Nils Bars +Date: Mon, 17 Jan 2022 16:53:16 +0000 +Subject: [PATCH] Fix null pointer dereference and use of uninitialized data + +This fixes a bug that causes use of uninitialized heap data if `readbuf` fails +to read as many bytes as indicated by the extra field length attribute. +Furthermore, this fixes a null pointer dereference if an archive contains an +`EF_UNIPATH` extra field but does not have a filename set. + +Upstream: https://launchpadlibrarian.net/580782282/0001-Fix-null-pointer-dereference-and-use-of-uninitialized-data.patch +CVE: CVE-2021-4217 +Signed-off-by: Thomas Perale +--- + fileio.c | 5 ++++- + process.c | 6 +++++- + 2 files changed, 9 insertions(+), 2 deletions(-) + +diff --git a/fileio.c b/fileio.c +index 14460f3..1dc319e 100644 +--- a/fileio.c ++++ b/fileio.c +@@ -2310,8 +2310,11 @@ int do_string(__G__ length, option) /* return PK-type error code */ + seek_zipf(__G__ G.cur_zipfile_bufstart - G.extra_bytes + + (G.inptr-G.inbuf) + length); + } else { +- if (readbuf(__G__ (char *)G.extra_field, length) == 0) ++ unsigned bytes_read = readbuf(__G__ (char *)G.extra_field, length); ++ if (bytes_read == 0) + return PK_EOF; ++ if (bytes_read != length) ++ return PK_ERR; + /* Looks like here is where extra fields are read */ + if (getZip64Data(__G__ G.extra_field, length) != PK_COOL) + { +diff --git a/process.c b/process.c +index 5f8f6c6..de843a5 100644 +--- a/process.c ++++ b/process.c +@@ -2067,10 +2067,14 @@ int getUnicodeData(__G__ ef_buf, ef_len) + G.unipath_checksum = makelong(offset + ef_buf); + offset += 4; + ++ if (!G.filename_full) { ++ /* Check if we have a unicode extra section but no filename set */ ++ return PK_ERR; ++ } ++ + /* + * Compute 32-bit crc + */ +- + chksum = crc32(chksum, (uch *)(G.filename_full), + strlen(G.filename_full)); + +-- +2.25.1 diff --git a/package/unzip/unzip.mk b/package/unzip/unzip.mk index 5436c7a46c..c362e6561f 100644 --- a/package/unzip/unzip.mk +++ b/package/unzip/unzip.mk @@ -51,6 +51,9 @@ UNZIP_IGNORE_CVES += CVE-2019-13232 # 0028-cve-2022-0529-and-cve-2022-0530.patch UNZIP_IGNORE_CVES += CVE-2022-0529 CVE-2022-0530 +# 0032-Fix-null-pointer-dereference-and-use-of-uninitialized-data.patch +UNZIP_IGNORE_CVES += CVE-2021-4217 + # unzip already defines _LARGEFILE_SOURCE and _LARGEFILE64_SOURCE when # necessary, redefining it on the command line causes some warnings. UNZIP_TARGET_CFLAGS = \