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Tue, 24 Jun 2025 13:03:58 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 6K4QAz6iWmjqYQAAD6G6ig (envelope-from ); Tue, 24 Jun 2025 13:03:58 +0000 From: Vlastimil Babka Date: Tue, 24 Jun 2025 15:03:46 +0200 Subject: [PATCH v2 2/4] mm, madvise: extract mm code from prctl_set_vma() to mm/madvise.c Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250624-anon_name_cleanup-v2-2-600075462a11@suse.cz> References: <20250624-anon_name_cleanup-v2-0-600075462a11@suse.cz> In-Reply-To: <20250624-anon_name_cleanup-v2-0-600075462a11@suse.cz> To: Andrew Morton , "Liam R. Howlett" , Lorenzo Stoakes , David Hildenbrand , Jann Horn , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Colin Cross Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vlastimil Babka X-Mailer: b4 0.14.2 X-Spam-Flag: NO X-Spam-Score: -8.30 X-Spamd-Result: default: False [-8.30 / 50.00]; REPLY(-4.00)[]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCVD_TLS_ALL(0.00)[]; RCPT_COUNT_TWELVE(0.00)[12]; MIME_TRACE(0.00)[0:+]; TO_DN_SOME(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_HAS_DN(0.00)[]; R_RATELIMIT(0.00)[to_ip_from(RL7wgbib1ih6q11z93xiyrfhpt)]; FROM_EQ_ENVFROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.cz:mid,suse.cz:email] X-Spam-Level: Setting anon_name is done via madvise_set_anon_name() and behaves a lot of like other madvise operations. However, apparently because madvise() has lacked the 4th argument and prctl() not, the userspace entry point has been implemented via prctl(PR_SET_VMA, ...) and handled first by prctl_set_vma(). Currently prctl_set_vma() lives in kernel/sys.c but setting the vma->anon_name is mm-specific code so extract it to a new set_anon_vma_name() function under mm. mm/madvise.c seems to be the most straightforward place as that's where madvise_set_anon_name() lives. Stop declaring the latter in mm.h and instead declare set_anon_vma_name(). Signed-off-by: Vlastimil Babka Acked-by: David Hildenbrand Reviewed-by: Lorenzo Stoakes Reviewed-by: Suren Baghdasaryan --- include/linux/mm.h | 14 +++++++------- kernel/sys.c | 50 +------------------------------------------------- mm/madvise.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++= -- 3 files changed, 58 insertions(+), 58 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 0e0549f3d681f6c7a78e8dfa341a810e5a8f96c1..ef40f68c1183d4c95016575a4ee= 0171e12df9ba4 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4059,14 +4059,14 @@ unsigned long wp_shared_mapping_range(struct addres= s_space *mapping, #endif =20 #ifdef CONFIG_ANON_VMA_NAME -int madvise_set_anon_name(struct mm_struct *mm, unsigned long start, - unsigned long len_in, - struct anon_vma_name *anon_name); +int set_anon_vma_name(unsigned long addr, unsigned long size, + const char __user *uname); #else -static inline int -madvise_set_anon_name(struct mm_struct *mm, unsigned long start, - unsigned long len_in, struct anon_vma_name *anon_name) { - return 0; +static inline +int set_anon_vma_name(unsigned long addr, unsigned long size, + const char __user *uname) +{ + return -EINVAL; } #endif =20 diff --git a/kernel/sys.c b/kernel/sys.c index adc0de0aa364aebb23999f621717a5d32599921c..b153fb345ada28ea1a33386a32b= cce9cb1b23475 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2343,54 +2343,14 @@ int __weak arch_lock_shadow_stack_status(struct tas= k_struct *t, unsigned long st =20 #define PR_IO_FLUSHER (PF_MEMALLOC_NOIO | PF_LOCAL_THROTTLE) =20 -#ifdef CONFIG_ANON_VMA_NAME - -#define ANON_VMA_NAME_MAX_LEN 80 -#define ANON_VMA_NAME_INVALID_CHARS "\\`$[]" - -static inline bool is_valid_name_char(char ch) -{ - /* printable ascii characters, excluding ANON_VMA_NAME_INVALID_CHARS */ - return ch > 0x1f && ch < 0x7f && - !strchr(ANON_VMA_NAME_INVALID_CHARS, ch); -} - static int prctl_set_vma(unsigned long opt, unsigned long addr, unsigned long size, unsigned long arg) { - struct mm_struct *mm =3D current->mm; - const char __user *uname; - struct anon_vma_name *anon_name =3D NULL; int error; =20 switch (opt) { case PR_SET_VMA_ANON_NAME: - uname =3D (const char __user *)arg; - if (uname) { - char *name, *pch; - - name =3D strndup_user(uname, ANON_VMA_NAME_MAX_LEN); - if (IS_ERR(name)) - return PTR_ERR(name); - - for (pch =3D name; *pch !=3D '\0'; pch++) { - if (!is_valid_name_char(*pch)) { - kfree(name); - return -EINVAL; - } - } - /* anon_vma has its own copy */ - anon_name =3D anon_vma_name_alloc(name); - kfree(name); - if (!anon_name) - return -ENOMEM; - - } - - mmap_write_lock(mm); - error =3D madvise_set_anon_name(mm, addr, size, anon_name); - mmap_write_unlock(mm); - anon_vma_name_put(anon_name); + error =3D set_anon_vma_name(addr, size, (const char __user *)arg); break; default: error =3D -EINVAL; @@ -2399,14 +2359,6 @@ static int prctl_set_vma(unsigned long opt, unsigned= long addr, return error; } =20 -#else /* CONFIG_ANON_VMA_NAME */ -static int prctl_set_vma(unsigned long opt, unsigned long start, - unsigned long size, unsigned long arg) -{ - return -EINVAL; -} -#endif /* CONFIG_ANON_VMA_NAME */ - static inline unsigned long get_current_mdwe(void) { unsigned long ret =3D 0; diff --git a/mm/madvise.c b/mm/madvise.c index fca0e9b3e844ad766e83ac04cc0d7f4099c74005..7e8819b5e9a0f183213ffe19d7e= 52bd5fda5f49d 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -134,8 +134,8 @@ static int replace_anon_vma_name(struct vm_area_struct = *vma, return 0; } =20 -int madvise_set_anon_name(struct mm_struct *mm, unsigned long start, - unsigned long len_in, struct anon_vma_name *anon_name) +static int madvise_set_anon_name(struct mm_struct *mm, unsigned long start, + unsigned long len_in, struct anon_vma_name *anon_name) { unsigned long end; unsigned long len; @@ -2096,3 +2096,51 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const s= truct iovec __user *, vec, out: return ret; } + +#ifdef CONFIG_ANON_VMA_NAME + +#define ANON_VMA_NAME_MAX_LEN 80 +#define ANON_VMA_NAME_INVALID_CHARS "\\`$[]" + +static inline bool is_valid_name_char(char ch) +{ + /* printable ascii characters, excluding ANON_VMA_NAME_INVALID_CHARS */ + return ch > 0x1f && ch < 0x7f && + !strchr(ANON_VMA_NAME_INVALID_CHARS, ch); +} + +int set_anon_vma_name(unsigned long addr, unsigned long size, + const char __user *uname) +{ + struct anon_vma_name *anon_name =3D NULL; + struct mm_struct *mm =3D current->mm; + int error; + + if (uname) { + char *name, *pch; + + name =3D strndup_user(uname, ANON_VMA_NAME_MAX_LEN); + if (IS_ERR(name)) + return PTR_ERR(name); + + for (pch =3D name; *pch !=3D '\0'; pch++) { + if (!is_valid_name_char(*pch)) { + kfree(name); + return -EINVAL; + } + } + /* anon_vma has its own copy */ + anon_name =3D anon_vma_name_alloc(name); + kfree(name); + if (!anon_name) + return -ENOMEM; + } + + mmap_write_lock(mm); + error =3D madvise_set_anon_name(mm, addr, size, anon_name); + mmap_write_unlock(mm); + anon_vma_name_put(anon_name); + + return error; +} +#endif --=20 2.50.0