kata-containers/s390-tools
1
0
Fork 0
mirror of https://github.com/ibm-s390-linux/s390-tools.git synced 2026-08-05 02:14:52 +00:00
Code Issues Packages Projects Releases Wiki Activity

libseckey: Protect from symlink-following attacks

Browse Source 
When creating or writing files, make sure that the file is not a
sysmlink. Such files created by libseckey are typically stored inside
the zkey repository and the owner and mode of them are changed to.
allow read/write for the owner user and the 'zkeyadm' group. It
would allow a symlink-following attack if the file being created are
symlinks. Make sure to open such files with the 'O_NOFOLLOW' flag.

Assisted-by: IBM Bob:2.0.0
Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com>
Reviewed-by: Finn Callies <fcallies@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
This commit is contained in:
Ingo Franzki
2026-06-30 09:50:45 +02:00
committed by Jan Höppner
parent 94292dac54
commit 226728731c
1 changed files with 35 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

39
libseckey/sk_utilities.c
View File

@@ -10,10 +10,12 @@
#include <string.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stdbool.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <unistd.h>
#include <openssl/evp.h>
#include <openssl/sha.h>
@@ -811,6 +813,35 @@ out:
return rc;
}
static inline FILE *fopen_nofollow(const char *path, const char *mode)
{
int flags = O_NOFOLLOW;
int fd;
FILE *fp;
/* Determine flags based on mode */
if (mode[0] == 'r')
flags |= (mode[1] == '+') ? O_RDWR : O_RDONLY;
else if (mode[0] == 'w')
flags |= O_CREAT | O_TRUNC |
((mode[1] == '+') ? O_RDWR : O_WRONLY);
else if (mode[0] == 'a')
flags |= O_CREAT | O_APPEND |
((mode[1] == '+') ? O_RDWR : O_WRONLY);
else
return NULL;
fd = open(path, flags, 0600);
if (fd < 0)
return NULL;
fp = fdopen(fd, mode);
if (fp == NULL) {
close(fd);
return NULL;
}
return fp;
}
/**
* Reads a X.509 certificate from the specified PEM file.
@@ -863,7 +894,7 @@ int SK_UTIL_write_x509_certificate(const char *pem_filename, X509 *cert)
if (pem_filename == NULL || cert == NULL)
return -EINVAL;
fp = fopen(pem_filename, "w");
fp = fopen_nofollow(pem_filename, "w");
if (fp == NULL)
return -errno;
@@ -898,7 +929,7 @@ int SK_UTIL_write_x509_request(const char *pem_filename, X509_REQ *req,
if (pem_filename == NULL || req == NULL)
return -EINVAL;
fp = fopen(pem_filename, "w");
fp = fopen_nofollow(pem_filename, "w");
if (fp == NULL)
return -errno;
@@ -982,7 +1013,7 @@ int SK_UTIL_write_key_blob(const char *filename, unsigned char *key_blob,
if (filename == NULL || key_blob == NULL || key_blob_len == 0)
return -EINVAL;
fp = fopen(filename, "w");
fp = fopen_nofollow(filename, "w");
if (fp == NULL)
return -errno;
@@ -1047,7 +1078,7 @@ int SK_UTIL_write_public_key(const char *pem_filename, EVP_PKEY *pkey)
if (pem_filename == NULL || pkey == NULL)
return -EINVAL;
fp = fopen(pem_filename, "w");
fp = fopen_nofollow(pem_filename, "w");
if (fp == NULL)
return -errno;