John Baldwin 7485e6a867 telnet: Prevent buffer overflow in the user prompt for SRA ... The Secure RPC authenticator for telnet prompts the local user for the username to use for authentication. Previously it was using sprintf() into a buffer of 256 bytes, but the username received over the wire can be up to 255 bytes long which would overflow the prompt buffer. Fix this in two ways: First, use snprintf() and check for overflow. If the prompt buffer overflows, fail authentication without prompting the user. Second, add 10 bytes to the buffer size to account for the overhead of the prompt so that a maximally sized username fits. While here, replace a bare 255 in the subsequent telnet_gets call with an expression using sizeof() the relevant buffer. PR: 270263 Reported by: Robert Morris <rtm@lcs.mit.edu> Tested on: CHERI Reviewed by: emaste Differential Revision: https://reviews.freebsd.org/D49832 (cherry picked from commit 5737c2ae06e143e49496df2ab5a64f76d5456012)		2025-04-29 10:45:52 -04:00
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arpa	telnet: remove 3rd clause from Berkeley copyrights	2019-08-15 13:27:57 +00:00
libtelnet	telnet: Prevent buffer overflow in the user prompt for SRA	2025-04-29 10:45:52 -04:00
telnet	Fix snprintf truncation in telnet	2023-12-24 14:59:34 +01:00