diff options
Diffstat (limited to 'executor/common_linux.h')
| -rw-r--r-- | executor/common_linux.h | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/executor/common_linux.h b/executor/common_linux.h index d0a5c0741..6b4d96c25 100644 --- a/executor/common_linux.h +++ b/executor/common_linux.h @@ -4259,3 +4259,184 @@ static void setup_usb() // The macro is used in generated C code. #define CAST(f) ({void* p = (void*)f; p; }) #endif + +#if SYZ_EXECUTOR || __NR_syz_fuse_handle_req +#include <fcntl.h> +#include <linux/fuse.h> +#include <stddef.h> +#include <stdio.h> +#include <sys/stat.h> +#include <sys/types.h> + +// Struct shared between syz_fuse_handle_req() and the fuzzer. Used to provide +// a fuzzed response for each request type. +struct syz_fuse_req_out { + struct fuse_out_header* init; + struct fuse_out_header* lseek; + struct fuse_out_header* bmap; + struct fuse_out_header* poll; + struct fuse_out_header* getxattr; + struct fuse_out_header* lk; + struct fuse_out_header* statfs; + struct fuse_out_header* write; + struct fuse_out_header* read; + struct fuse_out_header* open; + struct fuse_out_header* attr; + struct fuse_out_header* entry; + struct fuse_out_header* dirent; + struct fuse_out_header* direntplus; + struct fuse_out_header* create_open; + struct fuse_out_header* ioctl; +}; + +// Link the reponse to the request and send it to /dev/fuse. +static int +fuse_send_response(int fd, + const struct fuse_in_header* in_hdr, + struct fuse_out_header* out_hdr) +{ + if (!out_hdr) { + debug("fuse_send_response: received a NULL out_hdr\n"); + return -1; + } + + out_hdr->unique = in_hdr->unique; + if (write(fd, out_hdr, out_hdr->len) == -1) { + debug("fuse_send_response > write failed: %d\n", errno); + return -1; + } + + return 0; +} + +// This function reads a request from /dev/fuse and tries to pick the correct +// response from the input struct syz_fuse_req_out (a3). Responses are still +// generated by the fuzzer. +static volatile long syz_fuse_handle_req(volatile long a0, // /dev/fuse fd. + volatile long a1, // Read buffer. + volatile long a2, // Buffer len. + volatile long a3) // syz_fuse_req_out. +{ + struct syz_fuse_req_out* req_out = (struct syz_fuse_req_out*)a3; + struct fuse_out_header* out_hdr = NULL; + char* buf = (char*)a1; + int buf_len = (int)a2; + int fd = (int)a0; + + if (!req_out) { + debug("syz_fuse_handle_req: received a NULL syz_fuse_req_out\n"); + return -1; + } + if (buf_len < FUSE_MIN_READ_BUFFER) { + debug("FUSE requires the read buffer to be at least %u\n", FUSE_MIN_READ_BUFFER); + return -1; + } + + int ret = read(fd, buf, buf_len); + if (ret == -1) { + debug("syz_fuse_handle_req > read failed: %d\n", errno); + return -1; + } + // Safe to do because ret > 0 (!= -1) and < FUSE_MIN_READ_BUFFER (= 8192). + if ((size_t)ret < sizeof(struct fuse_in_header)) { + debug("syz_fuse_handle_req: received a truncated FUSE header\n"); + return -1; + } + + const struct fuse_in_header* in_hdr = (const struct fuse_in_header*)buf; + debug("syz_fuse_handle_req: received opcode %d\n", in_hdr->opcode); + if (in_hdr->len > (uint32)ret) { + debug("syz_fuse_handle_req: received a truncated message\n"); + return -1; + } + + switch (in_hdr->opcode) { + case FUSE_GETATTR: + case FUSE_SETATTR: + out_hdr = req_out->attr; + break; + case FUSE_LOOKUP: + case FUSE_SYMLINK: + case FUSE_LINK: + case FUSE_MKNOD: + case FUSE_MKDIR: + out_hdr = req_out->entry; + break; + case FUSE_OPEN: + case FUSE_OPENDIR: + out_hdr = req_out->open; + break; + case FUSE_STATFS: + out_hdr = req_out->statfs; + break; + case FUSE_RMDIR: + case FUSE_RENAME: + case FUSE_RENAME2: + case FUSE_FALLOCATE: + case FUSE_SETXATTR: + case FUSE_REMOVEXATTR: + case FUSE_FSYNCDIR: + case FUSE_FSYNC: + case FUSE_SETLKW: + case FUSE_SETLK: + case FUSE_ACCESS: + case FUSE_FLUSH: + case FUSE_RELEASE: + case FUSE_RELEASEDIR: + // These opcodes do not have any reply data. Hence, we pick + // another response and only use the shared header. + out_hdr = req_out->init; + if (!out_hdr) { + debug("syz_fuse_handle_req: received a NULL out_hdr\n"); + return -1; + } + out_hdr->len = sizeof(struct fuse_out_header); + break; + case FUSE_READ: + out_hdr = req_out->read; + break; + case FUSE_READDIR: + out_hdr = req_out->dirent; + break; + case FUSE_READDIRPLUS: + out_hdr = req_out->direntplus; + break; + case FUSE_INIT: + out_hdr = req_out->init; + break; + case FUSE_LSEEK: + out_hdr = req_out->lseek; + break; + case FUSE_GETLK: + out_hdr = req_out->lk; + break; + case FUSE_BMAP: + out_hdr = req_out->bmap; + break; + case FUSE_POLL: + out_hdr = req_out->poll; + break; + case FUSE_GETXATTR: + case FUSE_LISTXATTR: + out_hdr = req_out->getxattr; + break; + case FUSE_WRITE: + out_hdr = req_out->write; + break; + case FUSE_FORGET: + // FUSE_FORGET expects no reply. + return 0; + case FUSE_CREATE: + out_hdr = req_out->create_open; + break; + case FUSE_IOCTL: + out_hdr = req_out->ioctl; + break; + default: + debug("syz_fuse_handle_req: unknown FUSE opcode\n"); + return -1; + } + + return fuse_send_response(fd, in_hdr, out_hdr); +} +#endif |