| https://bugs.gentoo.org/797358 |
| |
| From 21cb1dad1243f4c0a427d893babab12e48b60f0e Mon Sep 17 00:00:00 2001 |
| From: Masatake YAMATO <yamato@redhat.com> |
| Date: Sun, 20 Jun 2021 21:40:55 +0900 |
| Subject: [PATCH] Adjust alignment of buffer passed to stat() |
| |
| Close #160. |
| |
| The original code passes char[] buffer to stat(). |
| This can be cause a SIGBUS. |
| |
| #160 reported an actual crash on armv7a + glibc-2.33 platform. |
| See also https://sourceware.org/bugzilla/show_bug.cgi?id=27993. |
| |
| The issue is reported by @10ne1. |
| |
| Signed-off-by: Masatake YAMATO <yamato@redhat.com> |
| [Adrian: Backported to 4.94] |
| Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com> |
| --- a/misc.c |
| +++ b/misc.c |
| @@ -293,7 +293,15 @@ doinchild(fn, fp, rbuf, rbln) |
| */ |
| |
| int r_al, r_rbln; |
| - char r_arg[MAXPATHLEN+1], r_rbuf[MAXPATHLEN+1]; |
| + char r_arg[MAXPATHLEN+1]; |
| + union { |
| + char r_rbuf[MAXPATHLEN+1]; |
| + /* |
| + * This field is only for adjusting the alignment of r_rbuf that |
| + * can be used as an argument for stat(). |
| + */ |
| + struct stat _; |
| + } r; |
| int (*r_fn)(); |
| /* |
| * Close sufficient open file descriptors except Pipes[0] and |
| @@ -358,16 +366,16 @@ doinchild(fn, fp, rbuf, rbln) |
| || read(Pipes[0], r_arg, r_al) != r_al |
| || read(Pipes[0], (char *)&r_rbln, sizeof(r_rbln)) |
| != (int)sizeof(r_rbln) |
| - || r_rbln < 1 || r_rbln > (int)sizeof(r_rbuf)) |
| + || r_rbln < 1 || r_rbln > (int)sizeof(r.r_rbuf)) |
| break; |
| - zeromem (r_rbuf, r_rbln); |
| - rv = r_fn(r_arg, r_rbuf, r_rbln); |
| + zeromem (r.r_rbuf, r_rbln); |
| + rv = r_fn(r_arg, r.r_rbuf, r_rbln); |
| en = errno; |
| if (write(Pipes[3], (char *)&rv, sizeof(rv)) |
| != sizeof(rv) |
| || write(Pipes[3], (char *)&en, sizeof(en)) |
| != sizeof(en) |
| - || write(Pipes[3], r_rbuf, r_rbln) != r_rbln) |
| + || write(Pipes[3], r.r_rbuf, r_rbln) != r_rbln) |
| break; |
| } |
| (void) _exit(0); |
| -- |
| 2.32.0 |
| |
