| Message ID | CAGG=3QW4b9mqh9oGQ16NmMGbo4HVHmdM00Be1Qk97StCpW4xTA@mail.gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | hpfs: Annotate struct hpfs_dirent with __counted_by | expand |
On Mon, May 13, 2024 at 04:45:54PM -0700, Bill Wendling wrote: > Prepare for the coming implementation by GCC and Clang of the > __counted_by attribute. Flexible array members annotated with > __counted_by can have their accesses bounds-checked at run-time checking > via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE > (for strcpy/memcpy-family functions). > > Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> > Cc: Kees Cook <keescook@chromium.org> > Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> > Cc: Nathan Chancellor <nathan@kernel.org> > Cc: Nick Desaulniers <ndesaulniers@google.com> > Cc: Justin Stitt <justinstitt@google.com> > Cc: linux-kernel@vger.kernel.org > Cc: linux-hardening@vger.kernel.org > Cc: llvm@lists.linux.dev > Signed-off-by: Bill Wendling <morbo@google.com> > --- > fs/hpfs/hpfs.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/hpfs/hpfs.h b/fs/hpfs/hpfs.h > index 281dec8f636b..ac137787f1f9 100644 > --- a/fs/hpfs/hpfs.h > +++ b/fs/hpfs/hpfs.h > @@ -357,7 +357,7 @@ struct hpfs_dirent { > u8 ix; /* code page index (of filename), see > struct code_page_data */ > u8 namelen; /* file name length */ > - u8 name[]; /* file name */ > + u8 name[] __counted_by(namelen); /* file name */ > /* dnode_secno down; btree down pointer, if present, > follows name on next word boundary, or maybe it > precedes next dirent, which is on a word boundary. */ Looking through struct hpfs_dirent::name uses, I think everything checks out. I do see some confusing manipulations in hpfs_add_de(), though. I *think* it'll be okay, though. Reviewed-by: Kees Cook <keescook@chromium.org>
diff --git a/fs/hpfs/hpfs.h b/fs/hpfs/hpfs.h index 281dec8f636b..ac137787f1f9 100644 --- a/fs/hpfs/hpfs.h +++ b/fs/hpfs/hpfs.h @@ -357,7 +357,7 @@ struct hpfs_dirent { u8 ix; /* code page index (of filename), see struct code_page_data */ u8 namelen; /* file name length */ - u8 name[]; /* file name */ + u8 name[] __counted_by(namelen); /* file name */ /* dnode_secno down; btree down pointer, if present, follows name on next word boundary, or maybe it precedes next dirent, which is on a word boundary. */
Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions). Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Cc: Kees Cook <keescook@chromium.org> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Justin Stitt <justinstitt@google.com> Cc: linux-kernel@vger.kernel.org Cc: linux-hardening@vger.kernel.org Cc: llvm@lists.linux.dev Signed-off-by: Bill Wendling <morbo@google.com> --- fs/hpfs/hpfs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)