[dunfell] opkg: Fix bad memory acces error observe in file_read_line_alloc

In the case of a zero length string being returned by fgets(), the condition
checking for a trailing new line would perform a bad memory access outside
of `buf`. This might happen when line with a leading null byte is read.

Avoid this case by checking that the string has a length of at least one
byte.

Link: https://github.com/ndmsystems/opkg/commit/8b45a3c4cab95382beea1ecdddeb2e4a9ed14aba

Signed-off-by: virendra thakur <virendrak@kpit.com>
---
 ...possible-bad-memory-access-in-file_r.patch | 50 +++++++++++++++++++
 meta/recipes-devtools/opkg/opkg_0.4.2.bb      |  1 +
 2 files changed, 51 insertions(+)
 create mode 100644 meta/recipes-devtools/opkg/opkg/0001-file_util.c-fix-possible-bad-memory-access-in-file_r.patch

ACK. This is a valid bug fix backport from just after opkg_0.4.2's release.

On 1/23/24 00:28, virendra thakur wrote:
> [You don't often get email from thakur.virendra1810@gmail.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>
> In the case of a zero length string being returned by fgets(), the condition
> checking for a trailing new line would perform a bad memory access outside
> of `buf`. This might happen when line with a leading null byte is read.
>
> Avoid this case by checking that the string has a length of at least one
> byte.
>
> Link: https://github.com/ndmsystems/opkg/commit/8b45a3c4cab95382beea1ecdddeb2e4a9ed14aba
>
> Signed-off-by: virendra thakur <virendrak@kpit.com>
> ---
>   ...possible-bad-memory-access-in-file_r.patch | 50 +++++++++++++++++++
>   meta/recipes-devtools/opkg/opkg_0.4.2.bb      |  1 +
>   2 files changed, 51 insertions(+)
>   create mode 100644 meta/recipes-devtools/opkg/opkg/0001-file_util.c-fix-possible-bad-memory-access-in-file_r.patch
>
> diff --git a/meta/recipes-devtools/opkg/opkg/0001-file_util.c-fix-possible-bad-memory-access-in-file_r.patch b/meta/recipes-devtools/opkg/opkg/0001-file_util.c-fix-possible-bad-memory-access-in-file_r.patch
> new file mode 100644
> index 0000000000..bec21e67f4
> --- /dev/null
> +++ b/meta/recipes-devtools/opkg/opkg/0001-file_util.c-fix-possible-bad-memory-access-in-file_r.patch
> @@ -0,0 +1,50 @@
> +From 8b45a3c4cab95382beea1ecdddeb2e4a9ed14aba Mon Sep 17 00:00:00 2001
> +From: Jo-Philipp Wich <jo@mein.io>
> +Date: Wed, 1 Apr 2020 21:47:40 +0200
> +Subject: [PATCH 001/104] file_util.c: fix possible bad memory access in
> + file_read_line_alloc()
> +
> +In the case of a zero length string being returned by fgets(), the condition
> +checking for a trailing new line would perform a bad memory access outside
> +of `buf`. This might happen when line with a leading null byte is read.
> +
> +Avoid this case by checking that the string has a length of at least one
> +byte. Also change the unsigned int types to size_t to store length values
> +while we're at it.
> +
> +Upstream-Status: Backport [https://github.com/ndmsystems/opkg/commit/8b45a3c4cab95382beea1ecdddeb2e4a9ed14aba]
> +
> +Signed-off-by: Jo-Philipp Wich <jo@mein.io>
> +Signed-off-by: Alejandro del Castillo <alejandro.delcastillo@ni.com>
> +Signed-off-by: virendra thakur <virendrak@kpit.com>
> +---
> + libopkg/file_util.c | 7 ++-----
> + 1 file changed, 2 insertions(+), 5 deletions(-)
> +
> +diff --git a/libopkg/file_util.c b/libopkg/file_util.c
> +index fbed7b4..ee9f59d 100644
> +--- a/libopkg/file_util.c
> ++++ b/libopkg/file_util.c
> +@@ -127,17 +127,14 @@ char *file_readlink_alloc(const char *file_name)
> + */
> + char *file_read_line_alloc(FILE * fp)
> + {
> ++    size_t buf_len, line_size;
> +     char buf[BUFSIZ];
> +-    unsigned int buf_len;
> +     char *line = NULL;
> +-    unsigned int line_size = 0;
> +     int got_nl = 0;
> +
> +-    buf[0] = '\0';
> +-
> +     while (fgets(buf, BUFSIZ, fp)) {
> +         buf_len = strlen(buf);
> +-        if (buf[buf_len - 1] == '\n') {
> ++        if (buf_len > 0 && buf[buf_len - 1] == '\n') {
> +             buf_len--;
> +             buf[buf_len] = '\0';
> +             got_nl = 1;
> +--
> +2.25.1
> +
> diff --git a/meta/recipes-devtools/opkg/opkg_0.4.2.bb b/meta/recipes-devtools/opkg/opkg_0.4.2.bb
> index 55be6547c0..3ebc27c8ee 100644
> --- a/meta/recipes-devtools/opkg/opkg_0.4.2.bb
> +++ b/meta/recipes-devtools/opkg/opkg_0.4.2.bb
> @@ -16,6 +16,7 @@ SRC_URI = "http://downloads.yoctoproject.org/releases/${BPN}/${BPN}-${PV}.tar.gz
>              file://opkg.conf \
>              file://0001-opkg_conf-create-opkg.lock-in-run-instead-of-var-run.patch \
>              file://sourcedateepoch.patch \
> +           file://0001-file_util.c-fix-possible-bad-memory-access-in-file_r.patch \
>              file://run-ptest \
>   "
>
> --
> 2.25.1
>