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Message-ID: <f181ee98-152a-7555-f883-b179e88aeadd@linaro.org>
Date: Thu, 10 Dec 2020 15:35:10 -0300
From: Adhemerval Zanella <adhemerval.zanella@...aro.org>
To: Szabolcs Nagy <szabolcs.nagy@....com>, libc-alpha@...rceware.org
Cc: Mark Rutland <mark.rutland@....com>, kernel-hardening@...ts.openwall.com,
Catalin Marinas <catalin.marinas@....com>, linux-kernel@...r.kernel.org,
Jeremy Linton <jeremy.linton@....com>, Mark Brown <broonie@...nel.org>,
Topi Miettinen <toiwoton@...il.com>, Will Deacon <will@...nel.org>,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 5/6] elf: Pass the fd to note processing
On 27/11/2020 10:21, Szabolcs Nagy via Libc-alpha wrote:
> To handle GNU property notes on aarch64 some segments need to
> be mmaped again, so the fd of the loaded ELF module is needed.
>
> When the fd is not available (kernel loaded modules), then -1
> is passed.
>
> The fd is passed to both _dl_process_pt_gnu_property and
> _dl_process_pt_note for consistency. Target specific note
> processing functions are updated accordingly.
LGTM, thanks.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@...aro.org>
> ---
> elf/dl-load.c | 12 +++++++-----
> elf/rtld.c | 4 ++--
> sysdeps/aarch64/dl-prop.h | 6 +++---
> sysdeps/generic/dl-prop.h | 6 +++---
> sysdeps/generic/ldsodefs.h | 5 +++--
> sysdeps/x86/dl-prop.h | 6 +++---
> 6 files changed, 21 insertions(+), 18 deletions(-)
>
> diff --git a/elf/dl-load.c b/elf/dl-load.c
> index b0d65f32cc..74039f22a6 100644
> --- a/elf/dl-load.c
> +++ b/elf/dl-load.c
> @@ -837,10 +837,12 @@ _dl_init_paths (const char *llp, const char *source)
>
> /* Process PT_GNU_PROPERTY program header PH in module L after
> PT_LOAD segments are mapped. Only one NT_GNU_PROPERTY_TYPE_0
> - note is handled which contains processor specific properties. */
> + note is handled which contains processor specific properties.
> + FD is -1 for the kernel mapped main executable otherwise it is
> + the fd used for loading module L. */
>
> void
> -_dl_process_pt_gnu_property (struct link_map *l, const ElfW(Phdr) *ph)
> +_dl_process_pt_gnu_property (struct link_map *l, int fd, const ElfW(Phdr) *ph)
> {
> const ElfW(Nhdr) *note = (const void *) (ph->p_vaddr + l->l_addr);
> const ElfW(Addr) size = ph->p_memsz;
Ok.
> @@ -887,7 +889,7 @@ _dl_process_pt_gnu_property (struct link_map *l, const ElfW(Phdr) *ph)
> last_type = type;
>
> /* Target specific property processing. */
> - if (_dl_process_gnu_property (l, type, datasz, ptr) == 0)
> + if (_dl_process_gnu_property (l, fd, type, datasz, ptr) == 0)
> return;
>
> /* Check the next property item. */
Ok.
> @@ -1379,10 +1381,10 @@ cannot enable executable stack as shared object requires");
> switch (ph[-1].p_type)
> {
> case PT_NOTE:
> - _dl_process_pt_note (l, &ph[-1]);
> + _dl_process_pt_note (l, fd, &ph[-1]);
> break;
> case PT_GNU_PROPERTY:
> - _dl_process_pt_gnu_property (l, &ph[-1]);
> + _dl_process_pt_gnu_property (l, fd, &ph[-1]);
> break;
> }
>
Ok.
> diff --git a/elf/rtld.c b/elf/rtld.c
> index c4ffc8d4b7..ec62567580 100644
> --- a/elf/rtld.c
> +++ b/elf/rtld.c
> @@ -1540,10 +1540,10 @@ dl_main (const ElfW(Phdr) *phdr,
> switch (ph[-1].p_type)
> {
> case PT_NOTE:
> - _dl_process_pt_note (main_map, &ph[-1]);
> + _dl_process_pt_note (main_map, -1, &ph[-1]);
> break;
> case PT_GNU_PROPERTY:
> - _dl_process_pt_gnu_property (main_map, &ph[-1]);
> + _dl_process_pt_gnu_property (main_map, -1, &ph[-1]);
> break;
> }
>
Ok.
> diff --git a/sysdeps/aarch64/dl-prop.h b/sysdeps/aarch64/dl-prop.h
> index b0785bda83..2016d1472e 100644
> --- a/sysdeps/aarch64/dl-prop.h
> +++ b/sysdeps/aarch64/dl-prop.h
> @@ -35,13 +35,13 @@ _dl_open_check (struct link_map *m)
> }
>
> static inline void __attribute__ ((always_inline))
> -_dl_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph)
> +_dl_process_pt_note (struct link_map *l, int fd, const ElfW(Phdr) *ph)
> {
> }
>
> static inline int
> -_dl_process_gnu_property (struct link_map *l, uint32_t type, uint32_t datasz,
> - void *data)
> +_dl_process_gnu_property (struct link_map *l, int fd, uint32_t type,
> + uint32_t datasz, void *data)
> {
> if (type == GNU_PROPERTY_AARCH64_FEATURE_1_AND)
> {
Ok.
> diff --git a/sysdeps/generic/dl-prop.h b/sysdeps/generic/dl-prop.h
> index f1cf576fe3..df27ff8e6a 100644
> --- a/sysdeps/generic/dl-prop.h
> +++ b/sysdeps/generic/dl-prop.h
> @@ -37,15 +37,15 @@ _dl_open_check (struct link_map *m)
> }
>
> static inline void __attribute__ ((always_inline))
> -_dl_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph)
> +_dl_process_pt_note (struct link_map *l, int fd, const ElfW(Phdr) *ph)
> {
> }
>
> /* Called for each property in the NT_GNU_PROPERTY_TYPE_0 note of L,
> processing of the properties continues until this returns 0. */
> static inline int __attribute__ ((always_inline))
> -_dl_process_gnu_property (struct link_map *l, uint32_t type, uint32_t datasz,
> - void *data)
> +_dl_process_gnu_property (struct link_map *l, int fd, uint32_t type,
> + uint32_t datasz, void *data)
> {
> return 0;
> }
Ok.
> diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
> index b1da03cafe..89eab4719d 100644
> --- a/sysdeps/generic/ldsodefs.h
> +++ b/sysdeps/generic/ldsodefs.h
> @@ -933,8 +933,9 @@ extern void _dl_rtld_di_serinfo (struct link_map *loader,
> Dl_serinfo *si, bool counting);
>
> /* Process PT_GNU_PROPERTY program header PH in module L after
> - PT_LOAD segments are mapped. */
> -void _dl_process_pt_gnu_property (struct link_map *l, const ElfW(Phdr) *ph);
> + PT_LOAD segments are mapped from file FD. */
> +void _dl_process_pt_gnu_property (struct link_map *l, int fd,
> + const ElfW(Phdr) *ph);
>
>
> /* Search loaded objects' symbol tables for a definition of the symbol
Ok.
> diff --git a/sysdeps/x86/dl-prop.h b/sysdeps/x86/dl-prop.h
> index 89911e19e2..4eb3b85a7b 100644
> --- a/sysdeps/x86/dl-prop.h
> +++ b/sysdeps/x86/dl-prop.h
> @@ -145,15 +145,15 @@ _dl_process_cet_property_note (struct link_map *l,
> }
>
> static inline void __attribute__ ((unused))
> -_dl_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph)
> +_dl_process_pt_note (struct link_map *l, int fd, const ElfW(Phdr) *ph)
> {
> const ElfW(Nhdr) *note = (const void *) (ph->p_vaddr + l->l_addr);
> _dl_process_cet_property_note (l, note, ph->p_memsz, ph->p_align);
> }
>
> static inline int __attribute__ ((always_inline))
> -_dl_process_gnu_property (struct link_map *l, uint32_t type, uint32_t datasz,
> - void *data)
> +_dl_process_gnu_property (struct link_map *l, int fd, uint32_t type,
> + uint32_t datasz, void *data)
> {
> return 0;
> }
>
Ok.
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