From 7d2c5526ed85dcd7c81d91a3e2782db883366143 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Wed, 16 Jun 2021 18:59:57 -0700 Subject: linux-user: Introduce imgsrc_read, imgsrc_read_alloc MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Introduced and initialized, but not yet really used. These will tidy the current tests vs BPRM_BUF_SIZE. Reviewed-by: Alex Bennée Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Richard Henderson --- linux-user/linuxload.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 90 insertions(+) (limited to 'linux-user/linuxload.c') diff --git a/linux-user/linuxload.c b/linux-user/linuxload.c index 745cce70ab..3536dd8104 100644 --- a/linux-user/linuxload.c +++ b/linux-user/linuxload.c @@ -3,7 +3,9 @@ #include "qemu/osdep.h" #include "qemu.h" #include "user-internals.h" +#include "user-mmap.h" #include "loader.h" +#include "qapi/error.h" #define NGROUPS 32 @@ -76,6 +78,10 @@ static int prepare_binprm(struct linux_binprm *bprm) /* Make sure the rest of the loader won't read garbage. */ memset(bprm->buf + retval, 0, BPRM_BUF_SIZE - retval); } + + bprm->src.cache = bprm->buf; + bprm->src.cache_size = retval; + return retval; } @@ -139,6 +145,7 @@ int loader_exec(int fdexec, const char *filename, char **argv, char **envp, int retval; bprm->fd = fdexec; + bprm->src.fd = fdexec; bprm->filename = (char *)filename; bprm->argc = count(argv); bprm->argv = argv; @@ -173,3 +180,86 @@ int loader_exec(int fdexec, const char *filename, char **argv, char **envp, return retval; } + +bool imgsrc_read(void *dst, off_t offset, size_t len, + const ImageSource *img, Error **errp) +{ + ssize_t ret; + + if (offset + len <= img->cache_size) { + memcpy(dst, img->cache + offset, len); + return true; + } + + if (img->fd < 0) { + error_setg(errp, "read past end of buffer"); + return false; + } + + ret = pread(img->fd, dst, len, offset); + if (ret == len) { + return true; + } + if (ret < 0) { + error_setg_errno(errp, errno, "Error reading file header"); + } else { + error_setg(errp, "Incomplete read of file header"); + } + return false; +} + +void *imgsrc_read_alloc(off_t offset, size_t len, + const ImageSource *img, Error **errp) +{ + void *alloc = g_malloc(len); + bool ok = imgsrc_read(alloc, offset, len, img, errp); + + if (!ok) { + g_free(alloc); + alloc = NULL; + } + return alloc; +} + +abi_long imgsrc_mmap(abi_ulong start, abi_ulong len, int prot, + int flags, const ImageSource *src, abi_ulong offset) +{ + const int prot_write = PROT_READ | PROT_WRITE; + abi_long ret; + void *haddr; + + assert(flags == (MAP_PRIVATE | MAP_FIXED)); + + if (src->fd >= 0) { + return target_mmap(start, len, prot, flags, src->fd, offset); + } + + /* + * This case is for the vdso; we don't expect bad images. + * The mmap may extend beyond the end of the image, especially + * to the end of the page. Zero fill. + */ + assert(offset < src->cache_size); + + ret = target_mmap(start, len, prot_write, flags | MAP_ANON, -1, 0); + if (ret == -1) { + return ret; + } + + haddr = lock_user(VERIFY_WRITE, start, len, 0); + assert(haddr != NULL); + if (offset + len <= src->cache_size) { + memcpy(haddr, src->cache + offset, len); + } else { + size_t rest = src->cache_size - offset; + memcpy(haddr, src->cache + offset, rest); + memset(haddr + rest, 0, len - rest); + } + unlock_user(haddr, start, len); + + if (prot != prot_write) { + target_mprotect(start, len, prot); + } + + return ret; +} -- cgit 1.4.1 From f485be725d4a08c950bf6996e33c178bfbd98509 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Wed, 16 Jun 2021 19:37:00 -0700 Subject: linux-user: Tidy loader_exec MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Reorg the if cases to reduce indentation. Test for 4 bytes in the file before checking the signatures. Reviewed-by: Alex Bennée Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Richard Henderson --- linux-user/linuxload.c | 38 +++++++++++++++++++------------------- 1 file changed, 19 insertions(+), 19 deletions(-) (limited to 'linux-user/linuxload.c') diff --git a/linux-user/linuxload.c b/linux-user/linuxload.c index 3536dd8104..5b7e9ab983 100644 --- a/linux-user/linuxload.c +++ b/linux-user/linuxload.c @@ -154,31 +154,31 @@ int loader_exec(int fdexec, const char *filename, char **argv, char **envp, retval = prepare_binprm(bprm); - if (retval >= 0) { - if (bprm->buf[0] == 0x7f - && bprm->buf[1] == 'E' - && bprm->buf[2] == 'L' - && bprm->buf[3] == 'F') { - retval = load_elf_binary(bprm, infop); + if (retval < 4) { + return -ENOEXEC; + } + if (bprm->buf[0] == 0x7f + && bprm->buf[1] == 'E' + && bprm->buf[2] == 'L' + && bprm->buf[3] == 'F') { + retval = load_elf_binary(bprm, infop); #if defined(TARGET_HAS_BFLT) - } else if (bprm->buf[0] == 'b' - && bprm->buf[1] == 'F' - && bprm->buf[2] == 'L' - && bprm->buf[3] == 'T') { - retval = load_flt_binary(bprm, infop); + } else if (bprm->buf[0] == 'b' + && bprm->buf[1] == 'F' + && bprm->buf[2] == 'L' + && bprm->buf[3] == 'T') { + retval = load_flt_binary(bprm, infop); #endif - } else { - return -ENOEXEC; - } + } else { + return -ENOEXEC; } - - if (retval >= 0) { - /* success. Initialize important registers */ - do_init_thread(regs, infop); + if (retval < 0) { return retval; } - return retval; + /* Success. Initialize important registers. */ + do_init_thread(regs, infop); + return 0; } bool imgsrc_read(void *dst, off_t offset, size_t len, -- cgit 1.4.1 From d0b6b79323726e47b1e9e399870ab063883874d0 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Wed, 16 Jun 2021 21:08:15 -0700 Subject: linux-user: Replace bprm->fd with bprm->src.fd MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit There are only a couple of uses of bprm->fd remaining. Migrate to the other field. Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Richard Henderson --- linux-user/flatload.c | 8 ++++---- linux-user/linuxload.c | 5 ++--- linux-user/loader.h | 1 - 3 files changed, 6 insertions(+), 8 deletions(-) (limited to 'linux-user/linuxload.c') diff --git a/linux-user/flatload.c b/linux-user/flatload.c index fdcc4610fa..5b62aa0a2b 100644 --- a/linux-user/flatload.c +++ b/linux-user/flatload.c @@ -463,7 +463,7 @@ static int load_flat_file(struct linux_binprm * bprm, DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n"); textpos = target_mmap(0, text_len, PROT_READ|PROT_EXEC, - MAP_PRIVATE, bprm->fd, 0); + MAP_PRIVATE, bprm->src.fd, 0); if (textpos == -1) { fprintf(stderr, "Unable to mmap process text\n"); return -1; @@ -490,7 +490,7 @@ static int load_flat_file(struct linux_binprm * bprm, } else #endif { - result = target_pread(bprm->fd, datapos, + result = target_pread(bprm->src.fd, datapos, data_len + (relocs * sizeof(abi_ulong)), fpos); } @@ -540,10 +540,10 @@ static int load_flat_file(struct linux_binprm * bprm, else #endif { - result = target_pread(bprm->fd, textpos, + result = target_pread(bprm->src.fd, textpos, text_len, 0); if (result >= 0) { - result = target_pread(bprm->fd, datapos, + result = target_pread(bprm->src.fd, datapos, data_len + (relocs * sizeof(abi_ulong)), ntohl(hdr->data_start)); } diff --git a/linux-user/linuxload.c b/linux-user/linuxload.c index 5b7e9ab983..4a794f8cea 100644 --- a/linux-user/linuxload.c +++ b/linux-user/linuxload.c @@ -39,7 +39,7 @@ static int prepare_binprm(struct linux_binprm *bprm) int mode; int retval; - if (fstat(bprm->fd, &st) < 0) { + if (fstat(bprm->src.fd, &st) < 0) { return -errno; } @@ -69,7 +69,7 @@ static int prepare_binprm(struct linux_binprm *bprm) bprm->e_gid = st.st_gid; } - retval = read(bprm->fd, bprm->buf, BPRM_BUF_SIZE); + retval = read(bprm->src.fd, bprm->buf, BPRM_BUF_SIZE); if (retval < 0) { perror("prepare_binprm"); exit(-1); @@ -144,7 +144,6 @@ int loader_exec(int fdexec, const char *filename, char **argv, char **envp, { int retval; - bprm->fd = fdexec; bprm->src.fd = fdexec; bprm->filename = (char *)filename; bprm->argc = count(argv); diff --git a/linux-user/loader.h b/linux-user/loader.h index da6591fff0..a0834290e7 100644 --- a/linux-user/loader.h +++ b/linux-user/loader.h @@ -74,7 +74,6 @@ struct linux_binprm { char buf[BPRM_BUF_SIZE] __attribute__((aligned)); ImageSource src; abi_ulong p; - int fd; int e_uid, e_gid; int argc, envc; char **argv; -- cgit 1.4.1