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a=ed25519; pk=tC3hNkJQTpNX/gLKxTNQKDmiQl6QjBNCGKJINqAdJsE= X-Developer-Signature: v=1; a=ed25519-sha256; t=1711051448; l=1634; i=justinstitt@google.com; s=20230717; h=from:subject:message-id; bh=S6RP6uWmLdlEXkKQny/wqkGVsqJcl1gAUGPqZ6bCYiM=; b=ltUxZ2cpj94pnvyIBEzmfBEHQXiRRLeDTlLyWbffUabFpLWPDEAtsiKsRij39k9phe/VyFBxJ 50r/4jHF4KlATUMzXLzQG9U+LPWH6633/Y5LV4uwnne1EeG7KX+npD1 X-Mailer: b4 0.12.3 Message-ID: <20240321-strncpy-fs-binfmt_elf_fdpic-c-v2-1-0b6daec6cc56@google.com> Subject: [PATCH v2] binfmt: replace deprecated strncpy From: Justin Stitt To: Alexander Viro , Christian Brauner , Jan Kara , Eric Biederman , Kees Cook Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Justin Stitt Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. There is a _nearly_ identical implementation of fill_psinfo present in binfmt_elf.c -- except that one uses get_task_comm over strncpy(). Let's mirror that in binfmt_elf_fdpic.c Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncp= y-on-nul-terminated-strings [1] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt --- Changes in v2: - use get_task_comm (thanks Eric) - Link to v1: https://lore.kernel.org/r/20240321-strncpy-fs-binfmt_elf_fdpi= c-c-v1-1-fdde26c8989e@google.com --- Note: build-tested only. Found with: $ rg "strncpy\(" --- fs/binfmt_elf_fdpic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index 1920ed69279b..3314249e8674 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -1359,7 +1359,7 @@ static int fill_psinfo(struct elf_prpsinfo *psinfo, s= truct task_struct *p, SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid)); SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid)); rcu_read_unlock(); - strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname)); + get_task_comm(psinfo->pr_fname, p); =20 return 0; } --- base-commit: a4145ce1e7bc247fd6f2846e8699473448717b37 change-id: 20240320-strncpy-fs-binfmt_elf_fdpic-c-828286d76310 Best regards, -- Justin Stitt