CVE-2025-68183

Description

In the Linux kernel, the following vulnerability has been resolved:ima: dont clear IMA_DIGSIG flag when setting or removing non-IMA xattrCurrently when both IMA and EVM are in fix mode, the IMA signature willbe reset to IMA hash if a program first stores IMA signature insecurity.ima and then writes/removes some other security xattr for thefile.For example, on Fedora, after booting the kernel with ima_appraise=fixevm=fix ima_policy=appraise_tcb and installing rpm-plugin-ima,installing/reinstalling a package will not make good reference IMAsignature generated. Instead IMA hash is generated, # getfattr -m - -d -e hex /usr/bin/bash # file: usr/bin/bash security.ima=0x0404...This happens because when setting security.selinux, the IMA_DIGSIG flagthat had been set early was cleared. As a result, IMA hash is generatedwhen the file is closed.Similarly, IMA signature can be cleared on file close after removingsecurity xattr like security.evm or setting/removing ACL.Prevent replacing the IMA file signature with a file hash, by preventingthe IMA_DIGSIG flag from being reset.Heres a minimal C reproducer which sets security.selinux as the laststep which can also replaced by removing security.evm or setting ACL, #include #include #include #include #include #include int main() { const char* file_path = /usr/sbin/test_binary; const char* hex_string = 030204d33204490066306402304; int length = strlen(hex_string); char* ima_attr_value; int fd; fd = open(file_path, O_WRONLY|O_CREAT|O_EXCL, 0644); if (fd == -1) { perror(Error opening file); return 1; } ima_attr_value = (char*)malloc(length / 2 ); for (int i = 0, j = 0; i < length; i += 2, j++) { sscanf(hex_string + i, %2hhx, &ima_attr_value[j]); } if (fsetxattr(fd, security.ima, ima_attr_value, length/2, 0) == -1) { perror(Error setting extended attribute); close(fd); return 1; } const char* selinux_value= system_u:object_r:bin_t:s0; if (fsetxattr(fd, security.selinux, selinux_value, strlen(selinux_value), 0) == -1) { perror(Error setting extended attribute); close(fd); return 1; } close(fd); return 0; }

Risk Information

Associated Vulnerability

Patch Details

References

https://nvd.nist.gov/vuln/detail/CVE-2023-1234
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-1234