From 6f110c7e2ba531904f3a2816917f1a433e3eb89d Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Mon, 20 Feb 2023 14:53:31 +0100 Subject: [PATCH 3/3] dmidecode: Do not let --dump-bin overwrite an existing file Make sure that the file passed to option --dump-bin does not already exist. In practice, it is rather unlikely that an honest user would want to overwrite an existing dump file, while this possibility could be used by a rogue user to corrupt a system file. Signed-off-by: Jean Delvare Reviewed-by: Jerry Hoemann --- dmidecode.c | 14 ++++++++++++-- man/dmidecode.8 | 3 ++- 2 files changed, 14 insertions(+), 3 deletions(-) diff --git a/dmidecode.c b/dmidecode.c index cfc7672..ef5040f 100644 --- a/dmidecode.c +++ b/dmidecode.c @@ -60,6 +60,7 @@ * https://www.dmtf.org/sites/default/files/DSP0270_1.0.1.pdf */ +#include #include #include #include @@ -5173,13 +5174,22 @@ static void dmi_table_string(const struct dmi_header *h, const u8 *data, u16 ver static int dmi_table_dump(const u8 *ep, u32 ep_len, const u8 *table, u32 table_len) { + int fd; FILE *f; - f = fopen(opt.dumpfile, "wb"); + fd = open(opt.dumpfile, O_WRONLY|O_CREAT|O_EXCL, 0666); + if (fd == -1) + { + fprintf(stderr, "%s: ", opt.dumpfile); + perror("open"); + return -1; + } + + f = fdopen(fd, "wb"); if (!f) { fprintf(stderr, "%s: ", opt.dumpfile); - perror("fopen"); + perror("fdopen"); return -1; } diff --git a/man/dmidecode.8 b/man/dmidecode.8 index 64dc7e7..d5b7f01 100644 --- a/man/dmidecode.8 +++ b/man/dmidecode.8 @@ -1,4 +1,4 @@ -.TH DMIDECODE 8 "January 2019" "dmidecode" +.TH DMIDECODE 8 "February 2023" "dmidecode" .\" .SH NAME dmidecode \- \s-1DMI\s0 table decoder @@ -132,6 +132,7 @@ hexadecimal and \s-1ASCII\s0. This option is mainly useful for debugging. Do not decode the entries, instead dump the DMI data to a file in binary form. The generated file is suitable to pass to \fB--from-dump\fR later. +\fIFILE\fP must not exist. .TP .BR " " " " "--from-dump FILE" Read the DMI data from a binary file previously generated using -- 2.40.1