Hi James,
Here's a pair of fixes that need to go upstream asap, please:
(1) Revert an incorrect fix to the keyrings UAPI for a C++ reserved word used as a struct member name. This change being reverted breaks existing userspace code and is thus incorrect.
Further, *neither* name is consistent with the one in the keyutils package public header.
(2) Fix the problem by using a union to make the name from keyutils available in parallel and make the 'private' name unavailable in C++ with cpp-conditionals.
David --- David Howells (1): keys: Fix the use of the C++ keyword "private" in uapi/linux/keyctl.h
Lubomir Rintel (1): Revert "uapi/linux/keyctl.h: don't use C++ reserved keyword as a struct member name"
include/uapi/linux/keyctl.h | 7 ++++++- security/keys/dh.c | 2 +- 2 files changed, 7 insertions(+), 2 deletions(-)
From: Lubomir Rintel lkundrak@v3.sk
This changes UAPI, breaking iwd and libell:
ell/key.c: In function 'kernel_dh_compute': ell/key.c:205:38: error: 'struct keyctl_dh_params' has no member named 'private'; did you mean 'dh_private'? struct keyctl_dh_params params = { .private = private, ^~~~~~~ dh_private
This reverts commit 8a2336e549d385bb0b46880435b411df8d8200e8.
Signed-off-by: Lubomir Rintel lkundrak@v3.sk Signed-off-by: David Howells dhowells@redhat.com cc: Randy Dunlap rdunlap@infradead.org cc: Mat Martineau mathew.j.martineau@linux.intel.com cc: Stephan Mueller smueller@chronox.de cc: James Morris jmorris@namei.org cc: "Serge E. Hallyn" serge@hallyn.com cc: Mat Martineau mathew.j.martineau@linux.intel.com cc: Andrew Morton akpm@linux-foundation.org cc: Linus Torvalds torvalds@linux-foundation.org cc: stable@vger.kernel.org ---
include/uapi/linux/keyctl.h | 2 +- security/keys/dh.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/keyctl.h b/include/uapi/linux/keyctl.h index 910cc4334b21..7b8c9e19bad1 100644 --- a/include/uapi/linux/keyctl.h +++ b/include/uapi/linux/keyctl.h @@ -65,7 +65,7 @@
/* keyctl structures */ struct keyctl_dh_params { - __s32 dh_private; + __s32 private; __s32 prime; __s32 base; }; diff --git a/security/keys/dh.c b/security/keys/dh.c index 3b602a1e27fa..711e89d8c415 100644 --- a/security/keys/dh.c +++ b/security/keys/dh.c @@ -300,7 +300,7 @@ long __keyctl_dh_compute(struct keyctl_dh_params __user *params, } dh_inputs.g_size = dlen;
- dlen = dh_data_from_key(pcopy.dh_private, &dh_inputs.key); + dlen = dh_data_from_key(pcopy.private, &dh_inputs.key); if (dlen < 0) { ret = dlen; goto out2;
The keyctl_dh_params struct in uapi/linux/keyctl.h contains the symbol "private" which means that the header file will cause compilation failure if #included in to a C++ program. Further, the patch that added the same struct to the keyutils package named the symbol "priv", not "private".
The previous attempt to fix this (commit 8a2336e549d3) did so by simply renaming the kernel's copy of the field to dh_private, but this then breaks existing userspace and as such has to be reverted (which is done by the preceding patch).
[And note, to those who think that wrapping the struct in extern "C" {} will work: it won't; that only changes how symbol names are presented to the assembler and linker.].
Instead, insert an anonymous union around the "private" member and add a second member in there with the name "priv" to match the one in the keyutils package. The "private" member is then wrapped in !__cplusplus cpp-conditionals to hide it from C++.
Fixes: ddbb41148724 ("KEYS: Add KEYCTL_DH_COMPUTE command") Fixes: 8a2336e549d3 ("uapi/linux/keyctl.h: don't use C++ reserved keyword as a struct member name") Signed-off-by: David Howells dhowells@redhat.com cc: Randy Dunlap rdunlap@infradead.org cc: Lubomir Rintel lkundrak@v3.sk cc: James Morris jmorris@namei.org cc: Mat Martineau mathew.j.martineau@linux.intel.com cc: Stephan Mueller smueller@chronox.de cc: Andrew Morton akpm@linux-foundation.org cc: Linus Torvalds torvalds@linux-foundation.org cc: stable@vger.kernel.org ---
include/uapi/linux/keyctl.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/keyctl.h b/include/uapi/linux/keyctl.h index 7b8c9e19bad1..0f3cb13db8e9 100644 --- a/include/uapi/linux/keyctl.h +++ b/include/uapi/linux/keyctl.h @@ -65,7 +65,12 @@
/* keyctl structures */ struct keyctl_dh_params { - __s32 private; + union { +#ifndef __cplusplus + __s32 private; +#endif + __s32 priv; + }; __s32 prime; __s32 base; };
On Mon, 2018-09-24 at 13:18 +0100, David Howells wrote:
The keyctl_dh_params struct in uapi/linux/keyctl.h contains the symbol "private" which means that the header file will cause compilation failure if #included in to a C++ program. Further, the patch that added the same struct to the keyutils package named the symbol "priv", not "private".
The previous attempt to fix this (commit 8a2336e549d3) did so by simply renaming the kernel's copy of the field to dh_private, but this then breaks existing userspace and as such has to be reverted (which is done by the preceding patch).
[And note, to those who think that wrapping the struct in extern "C" {} will work: it won't; that only changes how symbol names are presented to the assembler and linker.].
Instead, insert an anonymous union around the "private" member and add a second member in there with the name "priv" to match the one in the keyutils package. The "private" member is then wrapped in !__cplusplus cpp-conditionals to hide it from C++.
Fixes: ddbb41148724 ("KEYS: Add KEYCTL_DH_COMPUTE command") Fixes: 8a2336e549d3 ("uapi/linux/keyctl.h: don't use C++ reserved keyword as a struct member name") Signed-off-by: David Howells dhowells@redhat.com cc: Randy Dunlap rdunlap@infradead.org cc: Lubomir Rintel lkundrak@v3.sk cc: James Morris jmorris@namei.org cc: Mat Martineau mathew.j.martineau@linux.intel.com cc: Stephan Mueller smueller@chronox.de cc: Andrew Morton akpm@linux-foundation.org cc: Linus Torvalds torvalds@linux-foundation.org cc: stable@vger.kernel.org
include/uapi/linux/keyctl.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/keyctl.h b/include/uapi/linux/keyctl.h index 7b8c9e19bad1..0f3cb13db8e9 100644 --- a/include/uapi/linux/keyctl.h +++ b/include/uapi/linux/keyctl.h @@ -65,7 +65,12 @@ /* keyctl structures */ struct keyctl_dh_params {
- __s32 private;
- union {
+#ifndef __cplusplus
__s32 private;+#endif
__s32 priv;- }; __s32 prime; __s32 base;
};
Thank you, checked that this works fine for libell build.
Tested-by: Lubomir Rintel lkundrak@v3.sk
Perhaps you may want to call the C++ friendly field "dh_private", because there might be C++ users that utilize it already. (The chance might be negligible though.).
Lubo
On Mon, 24 Sep 2018, David Howells wrote:
The keyctl_dh_params struct in uapi/linux/keyctl.h contains the symbol "private" which means that the header file will cause compilation failure if #included in to a C++ program. Further, the patch that added the same struct to the keyutils package named the symbol "priv", not "private".
The previous attempt to fix this (commit 8a2336e549d3) did so by simply renaming the kernel's copy of the field to dh_private, but this then breaks existing userspace and as such has to be reverted (which is done by the preceding patch).
[And note, to those who think that wrapping the struct in extern "C" {} will work: it won't; that only changes how symbol names are presented to the assembler and linker.].
Instead, insert an anonymous union around the "private" member and add a second member in there with the name "priv" to match the one in the keyutils package. The "private" member is then wrapped in !__cplusplus cpp-conditionals to hide it from C++.
Fixes: ddbb41148724 ("KEYS: Add KEYCTL_DH_COMPUTE command") Fixes: 8a2336e549d3 ("uapi/linux/keyctl.h: don't use C++ reserved keyword as a struct member name") Signed-off-by: David Howells dhowells@redhat.com cc: Randy Dunlap rdunlap@infradead.org cc: Lubomir Rintel lkundrak@v3.sk cc: James Morris jmorris@namei.org cc: Mat Martineau mathew.j.martineau@linux.intel.com cc: Stephan Mueller smueller@chronox.de cc: Andrew Morton akpm@linux-foundation.org cc: Linus Torvalds torvalds@linux-foundation.org cc: stable@vger.kernel.org
include/uapi/linux/keyctl.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/keyctl.h b/include/uapi/linux/keyctl.h index 7b8c9e19bad1..0f3cb13db8e9 100644 --- a/include/uapi/linux/keyctl.h +++ b/include/uapi/linux/keyctl.h @@ -65,7 +65,12 @@
/* keyctl structures */ struct keyctl_dh_params {
- __s32 private;
- union {
+#ifndef __cplusplus
__s32 private;+#endif
__s32 priv;- }; __s32 prime; __s32 base;
};
Thanks David. This is an important fix for existing C userspace code, it would create a headache now and in to the future if the keyctl.h change introduced in v4.19-rc3 made it in to an official release. Please merge, James!
Reviewed-By: Mat Martineau mathew.j.martineau@linux.intel.com
-- Mat Martineau Intel OTC
linux-stable-mirror@lists.linaro.org
-
David Howells -
Lubomir Rintel -
Mat Martineau