Date: Mon, 15 Jan 2024 23:11:52 GMT From: Kyle Evans <kevans@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 78345dbd7a00 - stable/13 - bhyveload: use a dirfd to support -h Message-ID: <202401152311.40FNBq46097944@gitrepo.freebsd.org>
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The branch stable/13 has been updated by kevans: URL: https://cgit.FreeBSD.org/src/commit/?id=78345dbd7a004e0a6d1b717e7dbc758ae67ca293 commit 78345dbd7a004e0a6d1b717e7dbc758ae67ca293 Author: Kyle Evans <kevans@FreeBSD.org> AuthorDate: 2024-01-03 22:17:59 +0000 Commit: Kyle Evans <kevans@FreeBSD.org> CommitDate: 2024-01-15 23:11:38 +0000 bhyveload: use a dirfd to support -h Don't allow lookups from the loader scripts, which in rare cases may be in guest control depending on the setup, to leave the specified host root. Open the root dir and strictly do RESOLVE_BENEATH lookups from there. cb_open() has been restructured a bit to work nicely with this, using fdopendir() in the directory case and just using the fd we already opened in the regular file case. hostbase_open() was split out to provide an obvious place to apply rights(4) if that's something we care to do. Reviewed by: allanjude (earlier version), markj (cherry picked from commit 6779d44bd878e3cf4723f7386b11da6508ab5431) --- usr.sbin/bhyveload/bhyveload.c | 85 ++++++++++++++++++++++++++++-------------- 1 file changed, 58 insertions(+), 27 deletions(-) diff --git a/usr.sbin/bhyveload/bhyveload.c b/usr.sbin/bhyveload/bhyveload.c index d3095483b797..797f8b88dad2 100644 --- a/usr.sbin/bhyveload/bhyveload.c +++ b/usr.sbin/bhyveload/bhyveload.c @@ -61,6 +61,7 @@ #include <machine/specialreg.h> #include <machine/vmm.h> +#include <assert.h> #include <dirent.h> #include <dlfcn.h> #include <errno.h> @@ -87,11 +88,11 @@ #define NDISKS 32 -static char *host_base; static struct termios term, oldterm; static int disk_fd[NDISKS]; static int ndisks; static int consin_fd, consout_fd; +static int hostbase_fd = -1; static int need_reinit; @@ -157,42 +158,61 @@ static int cb_open(void *arg __unused, const char *filename, void **hp) { struct cb_file *cf; - char path[PATH_MAX]; + struct stat sb; + int fd, flags; - if (!host_base) + cf = NULL; + fd = -1; + flags = O_RDONLY | O_RESOLVE_BENEATH; + if (hostbase_fd == -1) return (ENOENT); - strlcpy(path, host_base, PATH_MAX); - if (path[strlen(path) - 1] == '/') - path[strlen(path) - 1] = 0; - strlcat(path, filename, PATH_MAX); - cf = malloc(sizeof(struct cb_file)); - if (stat(path, &cf->cf_stat) < 0) { - free(cf); + /* Absolute paths are relative to our hostbase, chop off leading /. */ + if (filename[0] == '/') + filename++; + + /* Lookup of /, use . instead. */ + if (filename[0] == '\0') + filename = "."; + + if (fstatat(hostbase_fd, filename, &sb, AT_RESOLVE_BENEATH) < 0) return (errno); + + if (!S_ISDIR(sb.st_mode) && !S_ISREG(sb.st_mode)) + return (EINVAL); + + if (S_ISDIR(sb.st_mode)) + flags |= O_DIRECTORY; + + /* May be opening the root dir */ + fd = openat(hostbase_fd, filename, flags); + if (fd < 0) + return (errno); + + cf = malloc(sizeof(struct cb_file)); + if (cf == NULL) { + close(fd); + return (ENOMEM); } + cf->cf_stat = sb; cf->cf_size = cf->cf_stat.st_size; + if (S_ISDIR(cf->cf_stat.st_mode)) { cf->cf_isdir = 1; - cf->cf_u.dir = opendir(path); - if (!cf->cf_u.dir) - goto out; - *hp = cf; - return (0); - } - if (S_ISREG(cf->cf_stat.st_mode)) { + cf->cf_u.dir = fdopendir(fd); + if (cf->cf_u.dir == NULL) { + close(fd); + free(cf); + return (ENOMEM); + } + } else { + assert(S_ISREG(cf->cf_stat.st_mode)); cf->cf_isdir = 0; - cf->cf_u.fd = open(path, O_RDONLY); - if (cf->cf_u.fd < 0) - goto out; - *hp = cf; - return (0); + cf->cf_u.fd = fd; } - -out: - free(cf); - return (EINVAL); + *hp = cf; + return (0); } static int @@ -710,6 +730,17 @@ usage(void) exit(1); } +static void +hostbase_open(const char *base) +{ + + if (hostbase_fd != -1) + close(hostbase_fd); + hostbase_fd = open(base, O_DIRECTORY | O_PATH); + if (hostbase_fd == -1) + err(EX_OSERR, "open"); +} + int main(int argc, char** argv) { @@ -744,7 +775,7 @@ main(int argc, char** argv) break; case 'h': - host_base = optarg; + hostbase_open(optarg); break; case 'l':
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