Quali sono le conseguenze dell'allocazione e quindi del popolamento di un buffer estremamente grande in C? Può uno stack avere una dimensione massima e in tal caso quali sono i meccanismi di sicurezza che lo rafforzano.
What are the consequences of allocating and then populating an extremely large buffer in C?
Se un processo diventa troppo grande nella memoria virtuale, può causare thrashing .
Can a stack have a maximum size and if so what are the security mechanisms that enforce this.
Questa domanda è stata posta e ha risposto qui: come funziona il kernel di Linux impone limiti di dimensioni dello stack?
Correlati: Dimensioni dello stack Linux
Dalla getrlimit e setrlimit man page :
RLIMIT_STACK
This is the maximum size of the process stack, in bytes. Upon reaching this limit, a SIGSEGV signal is generated. To handle this signal, a process must employ an alternate signal stack (sigaltstack(2)).
Since Linux 2.6.23, this limit also determines the amount of space used for the process's command-line arguments and environment variables; for details, see execve(2).
I limiti come RLIMIT_STACK sono applicati dal kernel:
DESCRIPTION
The getrlimit() and setrlimit() system calls get and set resource limits respectively. Each resource has an associated soft and hard limit, as defined by the rlimit structure:
struct rlimit {
rlim_t rlim_cur; /* Soft limit */
rlim_t rlim_max; /* Hard limit (ceiling for rlim_cur) */
};
The soft limit is the value that the kernel enforces for the corresponding resource. The hard limit acts as a ceiling for the soft limit: an unprivileged process may set only its soft limit to a value in the range from 0 up to the hard limit, and (irreversibly) lower its hard limit. A privileged process (under Linux: one with the CAP_SYS_RESOURCE capability) may make arbitrary changes to either limit value.
The value RLIM_INFINITY denotes no limit on a resource (both in the structure returned by getrlimit() and in the structure passed to setrlimit()).