Date: Wed, 10 Dec 2025 10:58:05 +0000 From: Brooks Davis <brooks@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: ac79e2e025e0 - main - get*ent: be consistant about _ALIGN(p) - p Message-ID: <6939523d.8560.71c378b7@gitrepo.freebsd.org>
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The branch main has been updated by brooks: URL: https://cgit.FreeBSD.org/src/commit/?id=ac79e2e025e03b7038e3abc886e34a03f5ec2934 commit ac79e2e025e03b7038e3abc886e34a03f5ec2934 Author: Brooks Davis <brooks@FreeBSD.org> AuthorDate: 2025-12-10 10:57:34 +0000 Commit: Brooks Davis <brooks@FreeBSD.org> CommitDate: 2025-12-10 10:57:34 +0000 get*ent: be consistant about _ALIGN(p) - p Add an nscache specific inline function to calculate the misalignment rather than adding and subtracting _ALIGN(p) and p which can take the buffer far out of bound (undefined behavior in C and unsupported on CHERI). Reviewed by: kib Effort: CHERI upstreaming Obtained from: CheriBSD Sponsored by: DARPA Differential Revision: https://reviews.freebsd.org/D53945 --- lib/libc/gen/getgrent.c | 6 +++--- lib/libc/include/nscache.h | 8 ++++++++ lib/libc/net/gethostnamadr.c | 4 ++-- lib/libc/net/getnetnamadr.c | 4 ++-- lib/libc/net/getprotoent.c | 4 ++-- lib/libc/net/getservent.c | 4 ++-- lib/libc/rpc/getrpcent.c | 4 ++-- 7 files changed, 21 insertions(+), 13 deletions(-) diff --git a/lib/libc/gen/getgrent.c b/lib/libc/gen/getgrent.c index 508e3d63eb60..8819708556b9 100644 --- a/lib/libc/gen/getgrent.c +++ b/lib/libc/gen/getgrent.c @@ -347,16 +347,16 @@ grp_unmarshal_func(char *buffer, size_t buffer_size, void *retval, va_list ap, memcpy(&p, buffer + sizeof(struct group), sizeof(char *)); if (orig_buf_size + sizeof(struct group) + sizeof(char *) + - _ALIGN(p) - (size_t)p < buffer_size) { + __nss_buf_misalignment(p) < buffer_size) { *ret_errno = ERANGE; return (NS_RETURN); } orig_buf = (char *)_ALIGN(orig_buf); memcpy(orig_buf, buffer + sizeof(struct group) + sizeof(char *) + - _ALIGN(p) - (size_t)p, + __nss_buf_misalignment(p), buffer_size - sizeof(struct group) - sizeof(char *) - - _ALIGN(p) + (size_t)p); + __nss_buf_misalignment(p)); p = (char *)_ALIGN(p); NS_APPLY_OFFSET(grp->gr_name, orig_buf, p, char *); diff --git a/lib/libc/include/nscache.h b/lib/libc/include/nscache.h index aab29e411ddc..5932d103a4da 100644 --- a/lib/libc/include/nscache.h +++ b/lib/libc/include/nscache.h @@ -29,6 +29,8 @@ #ifndef __NS_CACHE_H__ #define __NS_CACHE_H__ +#include <sys/_align.h> + #include "nscachedcli.h" typedef int (*nss_cache_id_func_t)(char *, size_t *, va_list, void *); @@ -178,6 +180,12 @@ typedef struct _nss_cache_data { } nss_cache_data; __BEGIN_DECLS +static inline __ptrdiff_t +__nss_buf_misalignment(const void *p) +{ + return ((char *)_ALIGN(p) - (char *)p); +} + /* dummy function, which is needed to make nss_method_lookup happy */ extern int __nss_cache_handler(void *, void *, va_list); diff --git a/lib/libc/net/gethostnamadr.c b/lib/libc/net/gethostnamadr.c index b54ca8b2998e..6a8648ac693d 100644 --- a/lib/libc/net/gethostnamadr.c +++ b/lib/libc/net/gethostnamadr.c @@ -402,9 +402,9 @@ host_unmarshal_func(char *buffer, size_t buffer_size, void *retval, va_list ap, orig_buf = (char *)_ALIGN(orig_buf); memcpy(orig_buf, buffer + sizeof(struct hostent) + sizeof(char *) + - _ALIGN(p) - (size_t)p, + __nss_buf_misalignment(p), buffer_size - sizeof(struct hostent) - sizeof(char *) - - _ALIGN(p) + (size_t)p); + __nss_buf_misalignment(p)); p = (char *)_ALIGN(p); NS_APPLY_OFFSET(ht->h_name, orig_buf, p, char *); diff --git a/lib/libc/net/getnetnamadr.c b/lib/libc/net/getnetnamadr.c index 660de3302606..b380912955e8 100644 --- a/lib/libc/net/getnetnamadr.c +++ b/lib/libc/net/getnetnamadr.c @@ -249,9 +249,9 @@ net_unmarshal_func(char *buffer, size_t buffer_size, void *retval, va_list ap, orig_buf = (char *)_ALIGN(orig_buf); memcpy(orig_buf, buffer + sizeof(struct netent) + sizeof(char *) + - _ALIGN(p) - (size_t)p, + __nss_buf_misalignment(p), buffer_size - sizeof(struct netent) - sizeof(char *) - - _ALIGN(p) + (size_t)p); + __nss_buf_misalignment(p)); p = (char *)_ALIGN(p); NS_APPLY_OFFSET(ne->n_name, orig_buf, p, char *); diff --git a/lib/libc/net/getprotoent.c b/lib/libc/net/getprotoent.c index 9fcbf41530cf..5f25333caff3 100644 --- a/lib/libc/net/getprotoent.c +++ b/lib/libc/net/getprotoent.c @@ -265,9 +265,9 @@ __proto_unmarshal_func(char *buffer, size_t buffer_size, void *retval, orig_buf = (char *)_ALIGN(orig_buf); memcpy(orig_buf, buffer + sizeof(struct protoent) + sizeof(char *) + - _ALIGN(p) - (size_t)p, + __nss_buf_misalignment(p), buffer_size - sizeof(struct protoent) - sizeof(char *) - - _ALIGN(p) + (size_t)p); + __nss_buf_misalignment(p)); p = (char *)_ALIGN(p); NS_APPLY_OFFSET(proto->p_name, orig_buf, p, char *); diff --git a/lib/libc/net/getservent.c b/lib/libc/net/getservent.c index 26f68f24cc78..1cf7921ac679 100644 --- a/lib/libc/net/getservent.c +++ b/lib/libc/net/getservent.c @@ -1084,9 +1084,9 @@ serv_unmarshal_func(char *buffer, size_t buffer_size, void *retval, va_list ap, orig_buf = (char *)_ALIGN(orig_buf); memcpy(orig_buf, buffer + sizeof(struct servent) + sizeof(char *) + - (_ALIGN(p) - (size_t)p), + __nss_buf_misalignment(p), buffer_size - sizeof(struct servent) - sizeof(char *) - - (_ALIGN(p) - (size_t)p)); + __nss_buf_misalignment(p)); p = (char *)_ALIGN(p); NS_APPLY_OFFSET(serv->s_name, orig_buf, p, char *); diff --git a/lib/libc/rpc/getrpcent.c b/lib/libc/rpc/getrpcent.c index ee36c11b303f..a6eaac7079a3 100644 --- a/lib/libc/rpc/getrpcent.c +++ b/lib/libc/rpc/getrpcent.c @@ -778,9 +778,9 @@ rpc_unmarshal_func(char *buffer, size_t buffer_size, void *retval, va_list ap, orig_buf = (char *)_ALIGN(orig_buf); memcpy(orig_buf, buffer + sizeof(struct rpcent) + sizeof(char *) + - _ALIGN(p) - (size_t)p, + __nss_buf_misalignment(p), buffer_size - sizeof(struct rpcent) - sizeof(char *) - - _ALIGN(p) + (size_t)p); + __nss_buf_misalignment(p)); p = (char *)_ALIGN(p); NS_APPLY_OFFSET(rpc->r_name, orig_buf, p, char *);
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