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commit    291ec6e45ebe1a87f930a250ad3c6672472b9b19
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Mon Feb 14 16:25:46 2022 +0000
First released in: 15.0

    Suppress integer-overflow compiler warning for inconsistent sun_len.
    
    On AIX 7.1, struct sockaddr_un is declared to be 1025 bytes long,
    but the sun_len field that should hold the length is only a byte.
    Clamp the value we try to store to ensure it will fit in the field.
    
    (This coding might need adjustment if there are any machines out
    there where sun_len is as wide as size_t; but a preliminary survey
    suggests there's not, so let's keep it simple.)
    
    Discussion: https://postgr.es/m/2781112.1644819528@sss.pgh.pa.us


 src/common/ip.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/common/ip.c b/src/common/ip.c
index b01e0d0e619..cd73d49679d 100644
--- a/src/common/ip.c
+++ b/src/common/ip.c
@@ -232,8 +232,18 @@ getaddrinfo_unix(const char *path, const struct addrinfo *hintsp,
 		aip->ai_addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(path);
 	}
 
+	/*
+	 * The standard recommendation for filling sun_len is to set it to the
+	 * struct size (independently of the actual path length).  However, that
+	 * draws an integer-overflow warning on AIX 7.1, where sun_len is just
+	 * uint8 yet the struct size exceeds 255 bytes.  It's likely that nothing
+	 * is paying attention to sun_len on that platform, but we have to do
+	 * something with it.  To suppress the warning, clamp the struct size to
+	 * what will fit in sun_len.
+	 */
 #ifdef HAVE_STRUCT_SOCKADDR_STORAGE_SS_LEN
-	unp->sun_len = sizeof(struct sockaddr_un);
+	unp->sun_len = Min(sizeof(struct sockaddr_un),
+					   ((size_t) 1 << (sizeof(unp->sun_len) * BITS_PER_BYTE)) - 1);
 #endif
 
 	return 0;


[parent: fd2abeb7c2b2]